89 4.3 Merc Hard Warm Starts

[HighTrim]

Evening gents,

Need some thoughts on an IO. It is an 89 4.3 Merc Alpha One outdrive. Cold starts she fires fine, but excessive amount of black smoke. After about 5 minutes of idling, the smoke will dissapear, and as you can imagine, this can be embarassing. Usually have to leave the throttle up for a few minutes as well until she is warm. Warm starts (usually when in a lock, 5 minutes of down time while the lock moves) are hard, really have to pump the throttle, but worry about flooding her.

Compression is good, 180 psi across the board.

Gotta hop back over to the Johnny Rude forum, but Ill be back in a jiffy Im slowly turning to the dark side I do believe!

Tks for the help!

 

[Don S]

Re: 89 4.3 Merc Hard Warm Starts

Electric choke is adjusted either way too tight, or not working at all.

 

[HighTrim]

Re: 89 4.3 Merc Hard Warm Starts

Electric choke is adjusted either way too tight, or not working at all.

Tks Don, you are usually my saviour on the dark side!

Had some thoughts of my own, but never considered that, will have a peek and let you know what I find.

Tight lines, Chris

 

[HighTrim]

Re: 89 4.3 Merc Hard Warm Starts

...just thinking, and let me know if Im on track here, wouldnt it be more likely that she is adjusted too tight, as if it were not working at all, my cold starts would be more difficult

 

[Don S]

Re: 89 4.3 Merc Hard Warm Starts

A cold engine with a choke that is too tight would start easily, but would smoke a lot (Black smoke) until it finally opened enough to work properly. But when too tight, it would flood out a warm engine immediatly and it either wouldn't start, or would be very hard to start and require the throttle to be at wide open throttle to even think about starting.

 

[Bondo]

Re: 89 4.3 Merc Hard Warm Starts

Ayuh,...

I Agree it sounds like the Choke is Wacked....
Or,...
It could be Deeper into the Carb,...
But,...
None the Less, It's a Fuel Delivery Issue....

 

[Don S]

Re: 89 4.3 Merc Hard Warm Starts

One other thing you might check is the yellow/clear hose that goes from the fuel pump to the carb. If there is fuel in the hose, it could be flooding the engine. THe hose is there to keep gas from getting into the bilge if the diaphram for the pump fails. With excess gas getting to the carb, it would act just like a choke that is too tight.

 

[chiefalen]

Re: 89 4.3 Merc Hard Warm Starts

You of course you checked the oil, not overfilled, and smelled the oil also.

I know i should not have asked you.

One other question i shouldn't ask the fuel pump is giving the right pressure, and not to mush, as in a new pump would maybe do and not the right one ?

Excuse my questions if they are out of line.