Opti 250 Dies after idling for a few minutes

[GatorFL]

I have been having trouble with the motor stopping after idling for awhile, it idles fine, then dies. It seems like it doesn’t get enough fresh air while idling. It quit 3 times yesterday with the following conditions:
1st time, came out of the locks and forgot to turn on the fan, died after a few minutes of idling out
2nd time, fan on before we started idling, died after a few minutes of idling into the lock
3rd time, before hitting a bridge idle zone, we removed the engine cover completely, left the engine door open and it still died after a few minutes idling

Each time, it wanted to sit for 15 minutes before it would fire back up.

The air filter is new, new fan also, does it still seem like a fresh air problem? The fan is set to draw the air out, it seems like the only fresh air opportunity is the hole in the top on the opposite side of the motor. I am assuming the fan draws in fresh air from this hole? The boat runs fine otherwise.

Any push in the right direction would be great, as we aren’t wanting to take the boat out with it doing this.

 

[GatorFL]

Dr. Honda,

Any input on this issue? The family doesn’t really want to go out and worry about getting stranded!
Maybe it isn’t air, but fuel? I have replaced the air filter and main fuel filter.

 

[Dr Honda]

Sorry I missed this... but you should have popped it back up. Looks like it was way back in April.

Anyway... it's an Opti................... (thinking)

Since you have the fan on, and even open the cover... I'm going to say no, it's not an air issue. UNLESS... you have a leaky exhaust.


I'm going to guess:

1) The air or fuel pressure is low, and picks up with RPM.

2) Spark plugs are bad. (but they would generally cause other issues too)

3) Compression is getting low.

4) The physical stop on the throttle got moved.

Check those, and we can move on.

 

[SeptemberC]

Dr. Honda, is it true that Opti’s don’t like to idle for long periods of time since the fuel/oil ratio is lean during idle?

 

[Dr Honda]

They should idle for ever... just like the EFI engines will. They aren't "lean" for fuel at idle... it's the oil. As I recall... they push up to 120:1. (scary) But that's why they don't smoke much either.

 

[SeptemberC]

They should idle for ever... just like the EFI engines will. They aren't "lean" for fuel at idle... it's the oil. As I recall... they push up to 120:1. (scary) But that's why they don't smoke much either.

The mechanic that helped me do the reeds just happened to be telling me a story of a couple other jobs he had done this summer. Both were Opti’s but on fishing boats. I guess they were idling for long periods of time while fishing an area. I don’t recall what the failure was but he said it was because the oil mixture was so low at idle. You know me... I was just curious.