# Mercury 9.9 Intermittently Quits???



## Meerkat (Aug 10, 2008)

Looking for ideas on the cause of my problem.

My 2016 Mercury pro-kicker starts and runs just fine. I can troll for 2 or 3 hours without any problem. But then it will just quit like it is out of gas. It is electric start so put it in neutral, hit the starter and after a few tries it will start right up and run just fine for another 2 or 3 hours. 

I disconnected the line from the pump to the carb and cranked the motor. Fuel comes out no problem. I took the carb apart, cleaned everything and put it back together. Next time out - same problem.

I am thinking the float may be intermittently sticking closed? Any other suggestions on what I need to check? Anyone else have this issue? The carb kit for this motor is $115! So I want to home in on the issue before I start spending big bucks on the wrong problem.

And the kicker and the 200hp Opti main motor are both supplied by the same outlet from the main fuel tank that runs though a Yamaha water separating fuel filter. And the Opti runs just fine.

Thanks in advance for any ideas!


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## rangerpig250 (Apr 10, 2011)

Mine was doing that but it eventually got worse. I’m sure you checked it already but I had sediment in my fuel filter that would float around for a bit before finally blocking it enough to stall the motor out. I thought I had bigger problems but a simple filter change solved it.


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## Meerkat (Aug 10, 2008)

rangerpig250 said:


> Mine was doing that but it eventually got worse. I’m sure you checked it already but I had sediment in my fuel filter that would float around for a bit before finally blocking it enough to stall the motor out. I thought I had bigger problems but a simple filter change solved it.


Thanks! Filter looks fine and was changed in the spring. But I have a new one on order. I looked up 'boat' in the dictionary. It said: "Hole in the water into which you pour money'


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## leeabu (Apr 10, 2004)

Electronic ignition modules do that when they get hot.


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## Meerkat (Aug 10, 2008)

Rangerpig's reply got me thinking....

I checked the fuel intake for my kicker and I was wrong. It does _not_ go through the Yamaha water separating fuel filter. Learn something new every day! I thought it did. It goes straight from the main fuel tank to the motor.

Anyway - only filter is that little inline filter inside the cowling. So I disconnected the fuel line from the motor & cut the fuel line at the motor. I checked the inside of the fuel line and it was fresh and clear (had heard horror stories about ethanol causing inside of fuel lines to disintegrate). I then pumped fuel into a clean white container using the primer bulb & there were 5 or 6 small pieces of black dirt that came in with the fuel...

I reattached the fuel line to connector & to the motor. I disassembled the fuel pump and checked inside of fuel pump for dirt. It was clean.

I reassembled the fuel pump & disconnected the fuel line from the carb. I pumped fuel with the primer bulb through the system (filter then fuel pump) into my clean white container. No dirt.

Next will be to replace that little inline fuel filter. I have one on order.

Thanks for the input!


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## ohezjig (Feb 13, 2011)

Had the same problem. Both motors supplied by same fuel line. Put a shut off valve in the line. Valve is in off position or supply to main motor or feeds kicker only. Before fuel line to both motors . was told possible air in line when running kicker only. About 2 hrs. would shut down. Only 1 time out with new valve seemed ok.


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## rangerpig250 (Apr 10, 2011)

Filter was supposed to be white not brown! I heard two suggestions where it came from, one was ethanol ate lining of fuel line, second suggestion was the fuel stabilizer eventually leaves deposits after extended use. All I know was the filter change made her run like new again. Hope it helps in your case


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## Meerkat (Aug 10, 2008)

rangerpig250 said:


> Filter was supposed to be white not brown! I heard two suggestions where it came from, one was ethanol ate lining of fuel line, second suggestion was the fuel stabilizer eventually leaves deposits after extended use. All I know was the filter change made her run like new again. Hope it helps in your case
> View attachment 323119


Yeah - my filter is brown. There was also a brown film all over the inside of the carb when I cleaned it. I use Stabil 360 Marine. 

So what is a guy supposed to do? They tell you you have to use a fuel stabilizer to prevent the ethanol from breaking down and clogging up the fuel system and when you do, the stabilizer itself breaks down and leaves deposits. OMG! 

I just ordered the Mercury Quickare stabilizer and the Mercury Quicklean. We will see! Thanks Kip!


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## rangerpig250 (Apr 10, 2011)

Meerkat said:


> Yeah - my filter is brown. There was also a brown film all over the inside of the carb when I cleaned it. I use Stabil 360 Marine.
> 
> So what is a guy supposed to do? They tell you you have to use a fuel stabilizer to prevent the ethanol from breaking down and clogging up the fuel system and when you do, the stabilizer itself breaks down and leaves deposits. OMG!
> 
> I just ordered the Mercury Quickare stabilizer and the Mercury Quicklean. We will see! Thanks Kip!


Sure hope that solves the issue, keep us posted, I’m curious! I bought 2 spares that I keep on the boat now.


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## bountyhunter (Apr 28, 2004)

if you have the gray hose fuel line?get rid of it. its breaking down ,dissolving the clear liner.it just hasn,t chunked off into little pieces yet.


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## bustedrod (May 13, 2015)

what does your plug look like ? maybe chck coils


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## Outer sanctum (Feb 19, 2019)

Mine is doing the same ... guess I’m changing filters


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## Meerkat (Aug 10, 2008)

bountyhunter said:


> if you have the gray hose fuel line?get rid of it. its breaking down ,dissolving the clear liner.it just hasn,t chunked off into little pieces yet.


Thanks Bountyhunter. Did a quick search & there are multiple brands of hose out there that all say “good for ethanol’. Do you have a recommendation for a hose that is good?


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## moondog5814 (Apr 8, 2007)

I have the gray hose too. Just bought the motor this summer and it has been running good. I was wondering what type of hose would be best, also.


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## fastwater (Apr 1, 2014)

^^^ Check out Trident #365 fuel line. It's A1-15 USCG approved and gets great reviews. And when replacing fuel lines ...don't go cheap on primer bulb either. Just not worth it to put good fuel line on, mated with a cheap aftermarket primer bulb. Either go OEM or a BRP aftermarket primer bulb.

On that note...I don't think there's a fuel line made yet that's a 'one and done' deal with the alcohol in our gas.
Think it's best to change even quality fuel line at least every 3-4 years.


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## Meerkat (Aug 10, 2008)

Anyone have a recommendation on hose clamps. Have read about lubricating the barb before assembling so as not to damage the hose liner & to use the right clamps for the same reason. Over tightening can damage hose liner. 


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## s.a.m (Feb 22, 2016)

Meerkat said:


> Yeah - my filter is brown. There was also a brown film all over the inside of the carb when I cleaned it. I use Stabil 360 Marine.
> 
> So what is a guy supposed to do? They tell you you have to use a fuel stabilizer to prevent the ethanol from breaking down and clogging up the fuel system and when you do, the stabilizer itself breaks down and leaves deposits. OMG!
> 
> I just ordered the Mercury Quickare stabilizer and the Mercury Quicklean. We will see! Thanks Kip!


That brown film is why I won't use stabil, I run sea foam and nonethanol fuel


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## Meerkat (Aug 10, 2008)

Been doing an internet search on non-ethanol gas close to Lorain. Not finding much. Looks like the closest is in Vermilion.


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## bountyhunter (Apr 28, 2004)

not brand over the other but I won,t use the gray ever again. bought my last hose bulk footage at a dealer. think fastwater has some hose numbers for you.


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## Meerkat (Aug 10, 2008)

Thanks! Went OEM on new hose & primer bulb. Not cheap but neither are my motors. Good insurance. 

Added fuel line replacement to my 3 year schedule. 

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## bountyhunter (Apr 28, 2004)

yep when ten mile from the ramp a few bucks just seems silly.


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## chaddy721 (Mar 31, 2013)

I put an extra inline filter on mine. It's the clear big one from Walmart right on the gas line past the primer bulb. It really seem to help. I just run sea foam now also.


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## Lewzer (Apr 5, 2004)

> Been doing an internet search on non-ethanol gas close to Lorain. Not finding much. Looks like the closest is in Vermilion.


The only EtOH free gas I see in Lorain is Beaver Park North marina. Boats only, no portable tanks.


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## Meerkat (Aug 10, 2008)

Lewzer said:


> The only EtOH free gas I see in Lorain is Beaver Park North marina. Boats only, no portable tanks.


Thanks for the info. Looks like they are closed Oct 20 to May 1. If the lake is not frozen I fish so looks like I am stuck with the ethanol issue.


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## Misdirection (Jul 16, 2012)

I'm not sure how much fuel you guys need, but you can buy Ethanol free Truefuel at home depot in 5 gallon cans for $19.99. $15.98 if you buy 4 or more. 

https://www.homedepot.com/p/TruSouth-TruFuel-4-Cycle-Ethanol-Free-Fuel-6527206/205913140



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## leeabu (Apr 10, 2004)

Misdirection said:


> I'm not sure how much fuel you guys need, but you can buy Ethanol free Truefuel at home depot in 5 gallon cans for $19.99. $15.98 if you buy 4 or more.
> 
> https://www.homedepot.com/p/TruSouth-TruFuel-4-Cycle-Ethanol-Free-Fuel-6527206/205913140
> 
> ...


That is for a .8594 gal (110 oz) can not a 5 gal can!


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## Shad Rap (Nov 10, 2010)

Misdirection said:


> I'm not sure how much fuel you guys need, but you can buy Ethanol free Truefuel at home depot in 5 gallon cans for $19.99. $15.98 if you buy 4 or more.
> 
> https://www.homedepot.com/p/TruSouth-TruFuel-4-Cycle-Ethanol-Free-Fuel-6527206/205913140
> 
> ...


Those are not 5 gallon cans...it's like less than a gallon...but it is ethanol free nonetheless...


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## buckeyedude (Feb 5, 2008)

Meerkat said:


> Thanks for the info. Looks like they are closed Oct 20 to May 1. If the lake is not frozen I fish so looks like I am stuck with the ethanol issue.


Pretty sure the gas station in Huron close to the ramp has ethanol free gas at one of there pumps.


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## Misdirection (Jul 16, 2012)

leeabu said:


> That is for a .8594 gal (110 oz) can not a 5 gal can!


Yeah, I googled 5 gallon and didn't read the fine print! My bad...

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## Meerkat (Aug 10, 2008)

I just talked to Mercury. They said they do not have any record of issues similar to mine. Said to take it to a dealer. That idea does not fill me with enthusiasm. I get way better advice on OGF!


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## ohiojmj (Apr 16, 2004)

I hate to ask a personal question, but is your squeeze bulb staying hard? My bulb got soft with my main motor running without a problem but my 9.9 kicker would stall.


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## dwy8979 (Nov 17, 2015)

Meerkat said:


> Yeah - my filter is brown. There was also a brown film all over the inside of the carb when I cleaned it. I use Stabil 360 Marine.
> 
> So what is a guy supposed to do? They tell you you have to use a fuel stabilizer to prevent the ethanol from breaking down and clogging up the fuel system and when you do, the stabilizer itself breaks down and leaves deposits. OMG!
> 
> I just ordered the Mercury Quickare stabilizer and the Mercury Quicklean. We will see! Thanks Kip!


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## dwy8979 (Nov 17, 2015)

I always use non Ethanol gas for both my motors, a Yamaha F150 and my 9.9 high thrust kicker.


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## rangerpig250 (Apr 10, 2011)

ohiojmj said:


> I hate to ask a personal question, but is your squeeze bulb staying hard? My bulb got soft with my main motor running without a problem but my 9.9 kicker would stall.


That was the first symptom I noticed, could not get the 9.9 primer bulb to get hard (no jokes please). It always had in the past. New filter, line and bulb and it’s back to normal


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## s.a.m (Feb 22, 2016)

Pure-gas.org search your area
Alot more stations are carrying ( rec. Fuel) usually 90-91 octane, and ethanol free


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## Seaturd (Apr 14, 2004)

Joe - I run 87 octane Circle K gas, with ethanol, in both my Optimax and Pro-kicker and have had zero fuel related issues in either one. I replaced my primer bulbs and fuel lines this year for the first time in 5 yrs and neither appeared to have any damage. Regular automotive grade fuel hose is designed for ethanol and high fuel line pressures used in efi engines. Lube the barbed of the primer bulb with a little dish soap, push the hose on and double clamp both ends with screw type clamps. As much as you use your boat you shouldn't even need any fuel additives. I do run some Seafoam on occasion in the winter months.

I probably just jinxed the crap out of myself.


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## Meerkat (Aug 10, 2008)

Thanks Rob! For what it is worth the tech I spoke to at Mercury told me: “We design our motors to run on E10 fuel”. But he also said they recommend fuel stabilizer if the motor is going to sit for an extended period. So that is what I am going to do. 

Not knocking guys who use pure gas. If ethanol free gas was readily & practically available to me I would use it. 

I have new OEM fuel lines & bulb on order plus new fuel filter. I have cleaned everything out & rebuilt carb. I have dumped the Stabil in favor of the Merc stabilizer. 

Now I need This wind to quit so I can test it.


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## meisty66 (Jul 14, 2015)

I'm lucky enough to have ethanol free gas available in my area but I do carry a bottle of Star Tron Enzyme Fuel Treatment in the event that I need to fuel up away from home. From everything I've read and on the suggestion of the guy I use for outboard work, it's about the best fuel treatment out there. I was told, if you can't use ethanol free, the Star Tron additive will negate any of the negative affects of using ethanol. My mechanic told me that %85 of the issues he encounters anymore are ethanol related.


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## Meerkat (Aug 10, 2008)

meisty66 said:


> I'm lucky enough to have ethanol free gas available in my area but I do carry a bottle of Star Tron Enzyme Fuel Treatment in the event that I need to fuel up away from home. From everything I've read and on the suggestion of the guy I use for outboard work, it's about the best fuel treatment out there. I was told, if you can't use ethanol free, the Star Tron additive will negate any of the negative affects of using ethanol. My mechanic told me that %85 of the issues he encounters anymore are ethanol related.


Yeah! Merc tech said their motors are designed to “run” on E10 gas. He did not say what happens if you let untreated gas sit in your fuel system. 

We all know what happens if you leave untreated E10 in your snowblower over the summer.


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## bustedrod (May 13, 2015)

hahaha thats funny merc drops the timing back to burn crap gas.. i cant afford to run ethanol free in the boat, but in my ice auger and chain saw, weed eater i seperate my own. just put gas in big glass jug, pour in water and stirr like mad. when it seperates the good stuff is on top , siphon off and bam ethenol free ...cant believe how good stuff runs on it.


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## Meerkat (Aug 10, 2008)

So last 3 outings the kicker ran just fine. Based on everything I did, I am putting my money on the fuel filter being the problem. Thanks Rangerpig! 

And thanks to everyone else who contributed. It helped me think through possible causes. 


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## rangerpig250 (Apr 10, 2011)

Meerkat said:


> So last 3 outings the kicker ran just fine. Based on everything I did, I am putting my money on the fuel filter being the problem. Thanks Rangerpig!
> 
> And thanks to everyone else who contributed. It helped me think through possible causes.
> 
> ...


Great news Joe, glad to hear she’s running good again ! I remember how irritated I was when mine kept stalling. See you out there!!!


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## Meerkat (Aug 10, 2008)

Now that I am back at my computer (too windy for fishing) here is the complete list of what I ran through starting at the gas tank:

I am continuing to run E10 gas. I spoke to Mercury Technician who said they design their motors to run on E10 gas. If ethanol free gas was readily available to me I would use it.
I am now using the Mercury fuel additives Quikcare & Quikclean. The Mercury Tech told me E10 gas is fine but they recommend their additives. (Mercury has a Quikstore additive as well but my boat does not sit long enough to worry about that )
I have stopped using Stabil. My filter was brown & I got some intel that it was due to the Stabil breaking down (apparently it has a shelf life).
I replaced the fuel lines and primer bulb. Existing ones were OEM Mercury & I replaced them with OEM Mercury. Old ones looked fine but just to be sure... As pointed out the fuel line does have a liner. You have to look hard but it is there.
I used proper hose clamps on the fuel lines. Probably nothing to do with the problem I was having but I bought this boat new and whoever rigged it used zip ties!
Before I hooked the fuel line to the motor I hand pumped from the tank with the primer bulb to make sure the gas was running clean (no dirt).
I replaced the inline filter. This was replaced in the spring but as I said previously it was now brown. Also Rangerpig said replacing the filter is what fixed his problem.
I took the fuel pump apart. Everything seemed fine but it has a thin brown film on most parts. I cleaned it and reassembled it.
I took the carburetor apart. Everything seemed fine but it has a thin brown film on most parts. I cleaned it and reassembled it.
Lastly I put some clean fuel in a portable tank. I added a double dose of the Mercury Quikclean and ran the motor for 30 minutes on the portable tank. I let the motor sit for 24 hours with the Quikclean gas inside. (probably similar to what some guys recommended on the Seafoam treatment) 
This seems to have fixed the problem. But for what it is worth, my next steps were going to be rebuilding the fuel pump with new diaphram, etc. and then putting a new float and float valve in the carburetor.

Like I said in my previous post - thanks for all the input. Helped me to put together a plan.


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## miked913 (Feb 29, 2008)

Thanks Joe! Again a great concise read as to how and why! You're the best!

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## 40xmax (Jun 10, 2018)

Meerkat said:


> Anyone have a recommendation on hose clamps. Have read about lubricating the barb before assembling so as not to damage the hose liner & to use the right clamps for the same reason. Over tightening can damage hose liner.
> 
> 
> Sent from my iPhone using Tapatalk


stainless steel fuel injection hose clamps....jegs, summit racing etc...I use SS. 035 aviation safety wire...no leaks...just a PITA to sometimes work with...that said,I'd go with SS fuel injection hose clamps...maybe overkill in some views, but they don't leak...


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## Meerkat (Aug 10, 2008)

An update on zip ties for fuel lines. Real Reeltime sent me a PM about this. Seems that the OEM's use them but they are a special "marine" zip tie. UV resistant and have a radius on the tie piece to conform to the curvature of the hose. I never knew. I looked it up online and there is a detailed thread on Hull Truth about plastic zip ties for marine fuel hose. Some guys say it is fine (and OEM's use them) but others disagree. What is new in the world? 

Anyway - thanks to Real Reeltime for the info.


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## firemanmike2127 (Mar 17, 2013)

The outboard manufacturers have been using them for under hood fuel connections for a long time now. If you have hoses that have hardened over time they (or any other clamp) does not work well. With soft, properly fitted hoses the specialty tie straps work just fine. In the case of F/I motors with higher working pressures Oetiker clamps are the go to. Mike


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