Engine turns over fine cold, hard time when warm

[legoman67]

Well, the other day we ran our engine going into our boat on the ground, it start up fairly easily, we let it run for about 20 minutes well we made afew adjustments. Then shut it down for 5 minutes, after we tried to start it back up again, it would struggle and would turn slowly then stop, then speed up to normal starter speed, then stop, then slow all well the starter was getting power. It did start up after afew tries, but this didnt seem right. Anyways we let it run for another 10 minutes or so, then shut it down and put it away for the night.

Today i decided to go out and just try cranking it over. Hooked up the battery(did not charge it at all since the last time) and it turns over fine now.


Any ideas why it was turning over funny? We were adjusting the check air valve and the choke. could that have caused it?

Mercruiser 255MIE 1979, starter is freshly rebuilt with only 2 days of quick runs.

 

[Don S]

Re: Engine turns over fine cold, hard time when warm

Sounds like your timing is off. Possibly starter problem, cables???? condition, tightness????

 

[legoman67]

Re: Engine turns over fine cold, hard time when warm

starter is basically brand new, so i dont think that would be the issue, there arent a lot of connections happening when we run on the ground, just the solinoid on the starter, the coil, and the ground are the only things hooked up, not going through the slave. I guess its possible the ground is a bad connection, i will check that out aswell

It may be the timing, but it ran great once it was started. i will check it anyways though.

thanks

 

[mthieme]

Re: Engine turns over fine cold, hard time when warm

Did this issue exist before replacing the starter?
Do you have a temperature gauge and take note of engine temperature?

Outside of Don's suggestions, I'm thinking bad starter (or solenoid), engine overheating, or maybe tune-up.

 

[legoman67]

Re: Engine turns over fine cold, hard time when warm

Cant tell you if it happened before, we had to get a new starter before we could run it because of the mounting limitations in our boat.

It probably hasnt had a tune up in awhile, might be something to look into. Will they do it well the engine is on the ground?

No guages are hooked up on the ground, but the engine isnt hot, we did a water drip test on the head, and it took afew seconds to start to evaporate.

 

[Don S]

Re: Engine turns over fine cold, hard time when warm

It may be the timing, but it ran great once it was started.

They will sound great running on the floor without a load on it, especailly to an untrained ear, your timing is probably WAY off which makes it sound good.
Get a timing light and set it right and see what happens.