# 50 hp mercury thunderbolt no spark



## Big Country25 (Jun 23, 2008)

I have a 50 hp mercury thunderbolt 1975 I bought a few weeks ago. I have had it out 6-7 times and covered alot of water and it has ran great. I took it out yesterday and it ran great today put it in the water and it would not start checked it over and I don't have spark what should I check first? 
Thanks for any help!
BC25


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## JOE W (Jun 4, 2004)

if it tries to start (turn over) and you have no spark i would say stator!! if your 75 has 1


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## Dfrenzy (Dec 18, 2008)

I believe at that time they still used points. I would check there first. Good luck I hope it's something simple.


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## Ken G (Apr 9, 2004)

I'll tell you its not the points, that model year 50 hp didn't have them. Other than that I can't be much help without knowing the model designation, Thunderbolt is not the model. It will be either 500M, 500ML, 500E, or 500EL. The 4 models use 2 different ignition systems, the first 3 have a distributor and the 500EL does not.

Spend the $35.00 on a Seloc manual you will need it on a motor that old since most marine dealers will not work on them. The Seloc manual will describe how to troubleshoot the different ignition systems. You do not want to just randomly replace ignition parts as they are expensive, non-returnable, sometimes hard to find, and in some instances unavailable.

And when you figure it out let me know, I have a 1977 500EL with the same problem and an even different ignition system. It's been sitting for 2 or 3 years since it quit running and I haven't taken the time to troubleshoot it yet. I have too many other projects.


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## ncraft150 (Apr 5, 2004)

If it has a kill switch ALWAYS check that first. My oldest son pulled mine when he was young and I replaced all kinds of stuff before I saw him in the boat playing with it one day. Reconnected it and she fired right up. Hard lesson learned, but it is always first on my check list now. Ive saved 2 guys on the lake with this info before while they where having trouble. It is very common to do this if you have one. Probably everyone I know has done it at least once.


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