1996 Yamaha 250 hard start after sitting on water for a while

[bre3412]

Got a 1996 250 hp Yamaha on a 24ft Sea Chaser, just had it completely rebuilt. The motor starts perfectly every time, but for example, this past weekend, we went out to the islands with family, and it ran fine. We stopped to fish for about 30-45 minutes, and it took almost 10 minutes to get the motor to fire back up. Call the place that rebuilt it said its carbureted, (well no ****), something you got to deal with, called another guy he said to try to (rev) start it, tried that same issue 5-10 mins of winning on it then it bust off. Anybody out there got any suggestions

 

[cyclops222]

Mechanics that only do COMPUTER controlled engines.
You are screwed by mechanics in your area.

 

[lelyyy]

You ain't alone in this mess. My old Honda 150 carbureted outboard did the same crap. Cold starts were smooth, but after sitting on the water for 30+ minutes? Total nightmare. Figured out the fuel was either evaporating in the carbs or cooking into vapor lock from engine heat. Here's what worked for me: When I'm anchored fishing or taking a break, I cut the motor early and fire it up for 5 seconds every 10 minutes. Keeps fresh fuel flowing and prevents it from getting heat-soaked. Sounds dumb but it helped a bit. Maybe worth a shot for you?

 

[cyclops222]

Excessively HOT engine. Crummy gasoline.
I would get a infrared dot thermometer. And check temperature as soon as you stop the boat. But before turning off the engine.

Next time. Before stopping the engine. In NEUTRAL hold the engine speed at a fast idle. To allow cool circulating water to cool everything down. A ignition timing ADVANCED too much will cause a overheated engine. Complete rebuilt ? I would never allow that to be done.
Do not take the engine back to the place that rebuilt it.
They will bleed you of every dollar you have.
Better luck.

 

[bre3412]

Excessively HOT engine. Crummy gasoline.
I would get a infrared dot thermometer. And check temperature as soon as you stop the boat. But before turning off the engine.

Next time. Before stopping the engine. In NEUTRAL hold the engine speed at a fast idle. To allow cool circulating water to cool everything down. A ignition timing ADVANCED too much will cause a overheated engine. Complete rebuilt ? I would never allow that to be done.
Do not take the engine back to the place that rebuilt it.
They will bleed you of every dollar you have.
Better luck.

 

[bre3412]

appreciate the advice my friend, wouldn't that trigger the alarm if the engine was that hot???

 

[cyclops222]

Maybe Depends on what the alarm module is feeling for water. Some, most, engines do not sound OVERHEAT at even 212 F. Steam can be coming out in cars. No alarm to warn you. They save pennies by telling you to watch the dash meter.

 

[dingbat]

appreciate the advice my friend, wouldn't that trigger the alarm if the engine was that hot???

Hot is relative.......
E10 can "boil" at 149F depending on the pressure.
The boiling point of E0 (Regular 87 octane) is ~185F

Try letting the engine idle a bit to cool down before shutting off.
Try running E0 and see if that helps