# Muffs for test running?



## Star1pup (Aug 3, 2004)

I'm considering buying a set of muffs instead of hauling a garbage can to my boat when I test run the motor this spring. I had one person tell me that I could ruin the impellor that way, but others said it was fine. I'd like to hear how others feel and any recommendations as to brand of muffs.


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## polebender (Oct 29, 2011)

Any muffs will work fine! Just make sure you have a good steady flow of water. The only way you can do damage is to dry start it!


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## bountyhunter (Apr 28, 2004)

just don,t see how you could ruin a impeller ,hook up, turn water, on start engine.


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## Iowa Dave (Sep 27, 2009)

The only outboards you can ruin impeller or overheat on muffs are Verado and any others with nosecone pickups. Other than that you're totally fine with muffs.


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## turkeyt (Apr 13, 2006)

Don't turn the hose on full blast because that is too much pressure. When the motor is in the water you don't have that pressure like with a hose. That may be what they were talking about when they were talking ruin.


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## sherman51 (Apr 12, 2011)

I've been using muffs with the water pressure on high for some 30 yrs and have never blown my impeller. just make sure the water is on before cranking motor. if you will notice when you start your motor with the water on high there is little if any extra water comes out of the muffs.

there is 2 different types of muffs that I know of. the cheap one that puts water out on one side. then the ones that costs around 20.00 on ebay that splits the water and flows in both sides. either one will work but I like the better muffs myself. I just checked out amazon.com and they have the split muffs for around 15.00 with shipping. you cant go wrong at that price. and if you take care of them they will last for many yrs.
sherman


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## Workdog (Jan 10, 2007)

Use a good hose, keep the rpms under 1,500 and don't halfass the water flow. I had a mechanic collapse a hose and melt my impeller by running the motor up with a crappy hose.


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## sherman51 (Apr 12, 2011)

Workdog said:


> Use a good hose, keep the rpms under 1,500 and don't halfass the water flow. I had a mechanic collapse a hose and melt my impeller by running the motor up with a crappy hose.


good advice workdog
sherman


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## Sculpin67 (Dec 11, 2007)

Make sure that your outboard doesn't have a front water pick-up too. If so, put a piece of duct tape over them...


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## johnrude (Mar 29, 2009)

I have heard from some guys in the outboard mechanic field that your forcing water thru the system with muffs. so if your impeller is bad you won't know till you hit the lake to find out.


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## meats52 (Jul 23, 2014)

I have a set of muffs that I have been using for years. I have a 35hp Evinrude and I use the muffs to start it for the first time in spring. I've never had any issues using them.


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## Iowa Dave (Sep 27, 2009)

I've been using muffs to run all of my outboards on for like the past 20-25 years or so (ever since they started making muffs) and never had any problems. 

Lets say for arguments sake that the force of water is so great it flips your impeller arms the opposite direction they are supposed to be.(most residential water pressure is around 20-40 lbs or so) Well guess what? When you start the outboard they flip in the direction that they are supposed to be. You can't put enough pressure directly into the impeller or the water pump to do any damage as long as you have a known good impeller. If it's rotten then yeah it's going to take a dump and needed changing anyway. 

I've proven this many times by intentionally putting the impeller on backwards and as soon as I start the outboard they flip the correct direction and start pumping. Too many people worry about nothing. This isn't a problem to run them on the muffs!

If you are worried about too much water pressure just turn it on to a nice flow and start the outboard.

What you don't want to do is to run an outboard on the flush that is attached to the engine. Some you can others no. Check in your owners manual about your particular outboard on flushing the engine using the flush port. Most have been designed to simply flush the system without the engine running.


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## sherman51 (Apr 12, 2011)

just to give you an idea. I made a trip to fl and the motor hadn't been run for almost 3 yrs. we wanted to make sure the motor would even start. and this motor has to be primed with gas for it to start when its cold. so we put the muffs on and primed the carbs, put the shift handle in neutral and pushed the handle forward like everybody does with the old motors. i turned the water on and the motor fired right up and went to about 3500 rpm's before i could pull the handle back to neutral. we let it run about 1/2 hour reeving the motor up to about 2000 rpm's and after a half hour we decided to take it fishing.

today we decided to go fishing again and i got to thinking i couldn't remember if any water was coming out the pee hole. so i hooked up the muffs and fired her up, and sure enough no water. i got a piece of big weed eater line and started putting it up the pee hole. about 1" up the hole i felt something but i kept going as far as it would go then worked it in and out a few inches the pulled the line out and sure enough the water came out in a good healthy stream. and my motor was running on muffs all that time.

i also use muffs at home and have a well with a 40 to 60 lb pressure switch and it has never hurt my impeller. and the water never gets past your impeller or you would get water out the pee hole. JUST USE IT.

oh yea im running a 1980 115 hp inline 6 cyl on this boat. i have a mercruiser in my other boat. but i have used muffs on everything from a old 15 hp sea king to my mercruiser and i wouldn't take 500.00 for my muffs if i couldn't replace them. i always check mine out with muffs before putting them in the water.
sherman


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## Star1pup (Aug 3, 2004)

FYI: I just ordered a dual feed set of muffs. I had enough Cabela's points to pay for them. Now if spring would ever get here so I can uncover the boat and go fishing.


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## sherman51 (Apr 12, 2011)

Star1pup said:


> FYI: I just ordered a dual feed set of muffs. I had enough Cabela's points to pay for them. Now if spring would ever get here so I can uncover the boat and go fishing.


good deal on the split muffs. and a big congrats on having enough points to get the muffs at cabelas.

how do you think all the saltwater boats flush there motors to clean the salt out of there motor? they use muffs or the ones that flushes there motor usually use muffs. I've never heard about anyone having a problem with muffs.
sherman


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## fishfighter (Feb 15, 2015)

I second the dual feed muffs. Mine have always worked great.


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## bajuski (Apr 9, 2004)

johnrude said:


> I have heard from some guys in the outboard mechanic field that your forcing water thru the system with muffs. so if your impeller is bad you won't know till you hit the lake to find out.



I can agree with this. I use muffs on my alpha one all the time and think they're a great way to run up your engine but you should take that into consideration. Even if the vanes on your impeller are damaged or missing, your house pressure is more than enough to cool your engine. That's why my first trip out for the year I fully warm up my engine on the water making sure my water temp stabilizes at 170 degrees before I shove out!


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## walleyechaser (Apr 13, 2004)

Just make sure you turn the water on with enough flow don't be afraid to turn the flow up more water is better


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## Star1pup (Aug 3, 2004)

I checked with this forum and also friends with experience and all agreed that muffs would be fine with my 9.9 Mercury 4-stroke so I tried it and it would not pump the water up and out. I even had a friend who does this all the time with his motor and we could not get it to work. I was afraid to run more than a few seconds for fear of ruining the motor. I finally drug the metal garbage cab up to the boat, filled it with water and the motor pumped water up and out immediately.

I still don't know why, but it sure is interesting. Could it be just that model of Mercury? It's a 9.9 Bigfoot.


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## brent k (Nov 10, 2013)

Interesting i have never been able to get my merc to pee on muffs. Its a 74 mercury 50hp blue band thunderbolt. 
Now as soon as i put it in barrel no problems it pees good


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## MOBIL4 (Jan 30, 2011)

I have a 2014 mercury Bigfoot 9.9. I muffed it this spring. Had no problem getting it to
Pee. Had to keep adjusting it to get a right seal. It only has one water supply to one muff.


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## sherman51 (Apr 12, 2011)

brent k said:


> Interesting i have never been able to get my merc to pee on muffs. Its a 74 mercury 50hp blue band thunderbolt.
> Now as soon as i put it in barrel no problems it pees good


turn your water pressure on high. it need to have plenty of water.


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## sherman51 (Apr 12, 2011)

MOBIL4 said:


> I have a 2014 mercury Bigfoot 9.9. I muffed it this spring. Had no problem getting it to
> Pee. Had to keep adjusting it to get a right seal. It only has one water supply to one muff.


if you have the water pressure on high which you should your motor wont take all the water and you'll have excess water coming out around the muffs until the thermostat opens. its better to invest 20.00 in a set of double feed muffs then you'll fell more confident about using muffs. you can get a set of double feed motor flusher on ebay for something like 18.59 with free shipping.
sherman


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## brent k (Nov 10, 2013)

Ok so on muffs it wont pee till thermostat opens?


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## humpty dumpty (Nov 30, 2013)

Just a little note fellows.. when you store your outboard for long periods,, take a dab of grease and lightly cover the pee hole on the motor,, as mud wasps will nest in there and plug it up,, actually all that hole does is indicate that your water pump is working,,, mine has plugged up before and I take the hose off at the motor and clean it out so I don't push any debris back into the motor, hope this helps..


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## sherman51 (Apr 12, 2011)

Star1pup said:


> I'm considering buying a set of muffs instead of hauling a garbage can to my boat when I test run the motor this spring. I had one person tell me that I could ruin the impellor that way, but others said it was fine. I'd like to hear how others feel and any recommendations as to brand of muffs.


I have a seachoice motor flusher. the double flow muffs on ebay are just over 22.00 with free shipping.

I've been using muffs for so many yrs I cant even remember. and I've always turned the water on full blast and never harmed my impeller. and I intend to keep doing it. just think how much pressure in being forced to the impeller running 40 or 50 mph going down the lake with water being forced in both sides.

when first starting your motor you'll have extra water coming out around the muffs. but once the thermostat opens and you raise your rpm's to 1000 to 1500 rpm's the excess water will be going to your motor.

its always better to have to much water than not enough. if you don't feel comfortable running a full stream of water to your motor just contact the mfg of the muffs and ask what they recommend. if your motor didn't need the extra water why would they have made the duel flo muffs in the 1st place.

just make sure there is no kinks in your water hose, put the muffs on, turn the water on and start motor. after the motor warms up see how much water is coming out around your muffs. and always keep a check on your muffs to make sure they don't slip off the water intakes.

I've been around boaters and owned my 1st boat since back in about 77 or 78 and I've never heard from anyone that they damaged there impeller from using muffs with to much water pressure. I have a well and have a 40/60 pressure switch on it. so when I hook up my muffs I have 40 to 60 lbs of pressure going to my motors and I always start and run my motors before going to the lake for the 1st time every yr. I have a mercruiser alpha one outdrive. I have a 79 115 hp inline 6 cyl and I run full pressure to both motors.

my little brother died 3 yrs ago this may. after he died I just lost interest in my little boat with the 115 hp on it. I hadn't started it since he died so the motor just set until back in feb when I went to fl. I put the muffs on it and started it and let it run for awhile. I wasn't getting anything out the pee hole so I took a 2' piece of large weed eater line and pushed it up the pee hole as far as it would go. then worked it back and forth a few times and pulled it out. then I had a stream of water out the pee hole. but if using muffs on high pressure was going to damage the impeller it should have blown my old impeller out. I do plan to replace the old impeller before I start using the boat next month.

I am sorry for such a long post. but I am a firm believer in having enough water going to the motor so it don't over heat.
sherman


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## fishingguy (Jan 5, 2006)

My merc has two thermostats in it. Only drips a drops or two until the motor warms up, stats open, than the stream starts. My manual actually says not to turn the water on to full pressure. But, I don't think it matters much, just make sure you got a good water flow down there before you crank.


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