Merc 255MIE seems fuel starved until it warms up....

[legoman67]

1979 Mercruiser 255 MIE, freshly rebuilt Rochester quadrajet.

When the engine is cold it doesn't like to run very well. I prime it and it always fires right up, and then a few seconds later the idle just starts dropping and it dies. If i give it some throttle when it starts dying it will bog for a second then rev up(repeating this cycle will keep it going). Also, if i keep it above 1500 rpm while its warming up it doesn't seem to die as easily. Once the temp gauge starts to move the problem disappears and it easily settles into a 600rpm idle, and seems to operate perfectly.

Any ideas?

 

[Don S]

Re: Merc 255MIE seems fuel starved until it warms up....

Choke adjustment is the first thing that comes to mind.

 

[cr2k]

Re: Merc 255MIE seems fuel starved until it warms up....

Ditto, check the choke.

 

[legoman67]

Re: Merc 255MIE seems fuel starved until it warms up....

do you guys have any suggestions on what needs to be adjusted? from what i have been reading it sounds like its maybe opening too fast? How do i adjust that? I cant seem to find anything talking about when you dont have an electric choke...

 

[Bondo]

Re: Merc 255MIE seems fuel starved until it warms up....

I cant seem to find anything talking about when you dont have an electric choke...

Ayuh,... Does it Have a choke,..??

 

[legoman67]

Re: Merc 255MIE seems fuel starved until it warms up....

heres what im working with... bare with me...im still learning carbs

 

[Bondo]

Re: Merc 255MIE seems fuel starved until it warms up....

Ayuh,... It appears yer Missing most of the choke stove, 'n some linkages....
Fix that, 'n she'll probably run awhole lot Better...

 

[legoman67]

Re: Merc 255MIE seems fuel starved until it warms up....

Ayuh,... It appears yer Missing most of the choke stove, 'n some linkages....
Fix that, 'n she'll probably run awhole lot Better...

isnt the stove the thing mounted on the intake with the push rod coming up?

id find it VERY hard to believe i am missing parts... i have another carb the exact same which works great

 

[Bondo]

Re: Merc 255MIE seems fuel starved until it warms up....

isnt the stove the thing mounted on the intake with the push rod coming up?

id find it VERY hard to believe i am missing parts... i have another carb the exact same which works great

oooops,.. sorry,... Didn't see the control rod 1st time around,...

 

[legoman67]

Re: Merc 255MIE seems fuel starved until it warms up....

well, i swapped the vacuum diaphram, and all the ckoke linkages between the 2 carbs, and it didnt really make a difference. While it was running at ~1500rpm and still cold, i went down and push the choke tang, it did exactly what its been doing before, sputtered down and died...

Any suggestions? i think the timing may be slightly off as i can hear a pop in the exhaust every once in awhile... could this be exaggerating the issue?

And once again, and soon as the temp jumped up to the 100* mark, i could easily bring it down to an idle...

Maybe ill just live with warming it up at 1500 for a few minutes...

 

[Don S]

Re: Merc 255MIE seems fuel starved until it warms up....

Maybe ill just live with warming it up at 1500 for a few minutes...

Uhhhh, that's pretty much how it's done with carbed engines. Unlike EFI, they just don't start up and go perfectly when cold.

 

[legoman67]

Re: Merc 255MIE seems fuel starved until it warms up....

true, i guess im trying to get it beyond perfect..... haha...