Mercruiser 888 stalling after Hard run

legoman67

Chief Petty Officer
Joined
Oct 16, 2008
Messages
636
Having an annoying problem on my Dad's boat...cant figure it out.

circa 1978 Mercruiser 888, ford 302 block, holly 2 barrel carb, rebuilt less then 50 hours ago with brand new carb and everything.

Problem is the engine starts and runs fine cold. Fires first turn of the key. You can idle it around all day long with no problems(reaching operating temperature). Throttling up it runs smooth as well, and can cruise at 2-3000rpm easily for ever. When throttling down after cruising, below about 800rpm the engine sputters out and dies. The only way to get it going again is to wait for it too cool back down. Then it instantly fires back up. And again, can putt around at idle rpms(650) in the marina all day long.

Thought of Vapor lock, and pulled the flame arrestor off after it stalled to find that fuel was still squirting into the carb. Also tried pouring cold water over the fuel lines to no avail.

Spark is good, again, brand new coil and electronic distributor. Spark plugs were dry and normal looking.

The only other thing i can think of is a choke problem...but why would it run fine as long as you dont take it above idle....:confused:
 

Jswelte

Recruit
Joined
Jul 14, 2011
Messages
1
Re: Mercruiser 888 stalling after Hard run

I had a similar issue on a 1977 888 Mercruiser. Replaced the fuel pump. No further problems.
 

haulnazz15

Captain
Joined
Mar 9, 2009
Messages
3,720
Re: Mercruiser 888 stalling after Hard run

What position is the electric choke (I'm assuming electric) when you shut it down? Just wondering if it is flooding out by having the choke closed when you shut it off.
 

boathater

Recruit
Joined
Jul 14, 2011
Messages
1
Re: Mercruiser 888 stalling after Hard run

I would say you're problem is a vapor luck in the carb or fuel system due too heat
 

dewardknapp

Recruit
Joined
Jul 28, 2011
Messages
1
Re: Mercruiser 888 stalling after Hard run

I have a 1975 Sea Ray with the same motor, doing the same thing. Can you start it in Neutral? I can start it by giving it some fuel in neutral, but it will not idle long enough to shift into gear. When attempting to shift it acts like there is an electronic cutout switch taking over, or perhaps a choke issue.

Help would be appreciated regarding this issue.
 
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