Full Throttle Engine cut off / bog on 1986 Mecr 140

[bobafett]

I need some help! 87 18ft Sunbird had rough idle and bogged on full throttle acceleration, but on slow acceleration it would get up to speed. So I figured it was time for a mercarb rebuild. I soaked,replaced gaskets and installed new Acc. pump included with Sierra kit for the 2 bbl. Now Idle is better, but I still bog on quick full throttle which I need for skiing. What else could be the problem? Any advice would be great!

 

[bobafett]

Re: Full Throttle Engine cut off / bog on 1986 Mecr 140

I also noticed the vent line going from the fuel pump to the carb was clogged with bright green gum (fuel I think) on both ends of the line and green colored throughout. I cleaned open and re installed. Does this mean the Full throttle bog is caused by the fuel pump failing?

 

[Rhadley]

Re: Full Throttle Engine cut off / bog on 1986 Mecr 140

What is your engine? The 120HP has a notorious bog problem that is due to a poor carburetor design. The mercarb has the problem for sure, not sure about the rochester.

 

[bobafett]

Re: Full Throttle Engine cut off / bog on 1986 Mecr 140

It is a 1986 140 HP Merc

 

[bobafett]

Re: Full Throttle Engine cut off / bog on 1986 Mecr 140

Can the mech fuel pump be repaired? is there a filter in this pump?

 

[jeff13601]

Re: Full Throttle Engine cut off / bog on 1986 Mecr 140

I have never heard of them being repaired. The bog that I think that you are talking about is a hesitation when you gun the throttle. It appears it is a common prob for the 120 and 140 of that time period as everyone, me included, seems to have the same prob. I only fish so I dont care about it, although I have tried to remedy it and can not

 

[bobafett]

Re: Full Throttle Engine cut off / bog on 1986 Mecr 140

The bog at full throttle has gotten worse over the last few seasons (not just a hesitation) and now it will cause the engine to shut off. I need it for skiing. Since I already rebuilt the carb, I am replacing the plugs and considering replacing the fuel pump. I got a quote from autostore for a mech pump 1962 chevy II engine for $23. Will that fit and does that price sound right?

 

[jeff13601]

Re: Full Throttle Engine cut off / bog on 1986 Mecr 140

It will fit but dont use it. For that price it is for a truck or car. You should be spending another hundred for a marine. You need marine. You havent checked the pressure on the pump yet have you?

 

[bobafett]

Re: Full Throttle Engine cut off / bog on 1986 Mecr 140

I don't own any gauges to check pressure. Can I estimate by measuring flow into bottle? If so How much should it pump it say 10 sec? Also, what is the difference in a marine grade fuel pump and one for a car - for an extra $100 it better be worth it. Thanks again<br /><br />Also, if there is gas residue in the vent line doesn't that mean the pump needs to be replaced regardless of pressure?<br /><br />Could the green colored residuein the line come from starter fluid that I have had to spray in flame arrestor in the past?

 

[jeff13601]

Re: Full Throttle Engine cut off / bog on 1986 Mecr 140

Check your other post

 

[bobafett]

Re: Full Throttle Engine cut off / bog on 1986 Mecr 140

Thanks! Jeff