Runs Great Sometimes

[trent_tweeter]

'68-55-evinrude-55873R-has issues.
Starts instantly when cold with choke. Will run perferctly for 10-15 minutes ie slow med fast back to idle changing gears etc. After 15-20 minutes of running if slowed down to idle it will stall and then wont start for at least 5-10 minutes choke or no choke. If water is splashed on area of cylinder head where thermostat resides engine will start before waiting 5-10 minutes. I removed thermostat but problem still exists. Seems as long as it is running above half throttle and not brought down to idle it will literally run happily all day. Can't take the kids skiing with the situation as is. Rewired the entire motor under shroud last year and problem is still the same.
Any advice would be appreciated.

 

[tashasdaddy]

Re: Runs Great Sometimes

sounds like it is running hot due to poor circulation, Water Pump? put the Tstat back in, it is there for a reason. you also could have a coil, or power pack failing when it gets hot.

 

[F_R]

Re: Runs Great Sometimes

What spark plugs are you running? If they are the original surface-gap plugs, trash them and put in a set of Champion QL77JC4 plugs gapped to .030" Those motors and surface gap plugs were a big mistake that made the advertizing people happy but drove the mechanics nutso trying to keep them running. Pouring water on the head, you are cooling the plugs.

 

[trent_tweeter]

Re: Runs Great Sometimes

Thanks for reply,
Am using conventional type spark plugs.
Impeller replaced last spring.
Coil, condenser,points new.
Pack is not an issue.
Is there a way to check water circ?
Could it be a fuel pump/filter or carb issue?

 

[ezeke]

Re: Runs Great Sometimes

Check water circulation by putting your hand on the cylinder heads. If you can't keep it there for a full three count any time the engine is running, you are overheated and therefore not getting proper circulation.

At this point you may have already blown a head gasket, so be prepared to change it after you do your compression test.