1975 Envinrude 115 cuts out at WOT

First post - thanks in advance!<br /><br />I bought this motor last year. It started and idled very nicely on the trailer with the muffs on.<br /><br />The first day we ran it for about 3 hours and it ran just great at all speeds. Right near the end of the day the motor stalled suddenly, but it restarted.<br /><br />The next time out it ran for about 10 minuted before it cut out.<br /><br />When it cuts out it stops suddenly, no warning whatsoever. After it stops, the flywheel will not turn, the motor appears to be jammed tight. After a few minutes the starter motor has enough strength to budge it just a bit.<br /><br />The next day it starts fine again and runs great for about 10 minutes. Then the same thing happened.<br /><br />I am suspecting cooling problems, thinking hte engine may be overheating. I have started to change out the impeler and the therostats although they both appear to be in perfect condition (hence this post). Also, I have read in some posts that there is a overheat warning horn? I have not heard anything like that.<br /><br />Does this condition sound familiar to anyone?<br /><br />Thanks.

Re: 1975 Envinrude 115 cuts out at WOT

If it is an over-heat, and it has brought the engine to a complete stop, that is one of the worse things, next to lack of oil that can happen to an engine. You should probably pull the heads to have a look at the cylinder walls. You can do a compression test, but I would'nt trust it in this case.

Re: 1975 Envinrude 115 cuts out at WOT

Late last summer I took it to a marina to have them take a look at it. The guy changed the starter, said that it did not help and suggested that I write off the whole boat! I went and grabbed it back from him as quick as I could drive.<br /><br />While he was at it though he did run a compression etst and said it was fine (I foget the numbers). <br /><br />I'm quite the novice at this (getting th elower unit off and then back on was quite an accomplishment for me) - will pulling off the head covers be a big job? Will I need to put new gaskets on when I put it back together? What shoudl I be looking for on the cylender walls?

Re: 1975 Envinrude 115 cuts out at WOT

If this engine has been stopped by a over-heat siezure,more than once. There is a good chance the pistons', and cylinder walls' have been scored. With the head off, look for lenght long scratch's on the cylinder wall, or patch's of aluminum.

Re: 1975 Envinrude 115 cuts out at WOT

OldRusty, you very likely are seizing the engine up tight momentarily. Not good at all. Nonetheless, as long as you aren't out in the middle of the Atlantic with it, once you fix the problem it may run that way for a long time. <br /><br />How about checking the compression first, and getting back to us? In the meantime, if you are motivated, clean the carbs, particularly the main jet circuits.<br /><br />The heads are very easy to pull off. You 100% absolutely need new gaskets when you put the heads back on, and you need to torque them. Torque them again after the first decent run. Post back if any of this is unclear.<br /><br />Don't 'depend' on the motor the way it is. If you just want to ski or fish on a lake/river where you can always get towed in, no problem. But DO NOT venture out on the salt or Great Lakes where your life depends on that motor getting you back in.

Re: 1975 Envinrude 115 cuts out at WOT

Get a manual if you are going to get into an engine that siezed. There is more to it than tearing it apart and putting it back together with new parts. R. Johnson is right that you need to torque them properly but you need to know what foot pounds to torque them to and what order to torque them at. An OEM manual will take care of this.

Re: 1975 Envinrude 115 cuts out at WOT

Do not clean the carbs, do not replace the water pump, Pull the head, and take a look at the cylinder walls. Otherwize you are just throwing money, and time,at a siezed,and possibly badly damaged engine

Re: 1975 Envinrude 115 cuts out at WOT

Thanks for the tips guys. Sounds like the concensus is that it is a cooling problem at the root.<br /><br />- I'm on a small lake, so no worries about safety - thanks!<br />- time I have, money - well not for this 1975...<br />- I think I'm going to start by poking at the cooling system more first, I suspect that there is a block inthe pipes leading fromthe lower unti to the head - perhaps I'll make another post about that next week after my forst hack -we'll see!<br />- I'll leave the heads alone for now, definitely will check them out before I try anything else should I still have trouble once the cooling is in order<br /><br />Thanks again.