Accel problem

[Stuey_15]

I have the 4cylender 3lt carby fed mercruiser an it run fine on idle an sometimes when cold but once the engine is warm every time I go to accelerate the engine shutters an wont accelerate I back the throttle back to idle an its fine again an ideas on what to check??

0M361286

 

[thumpar]

Re: Accel problem

Check to make sure the choke is opening up and that the accelerator pump is working.

 

[Don S]

Re: Accel problem

If the choke is working, and the accelerator pump is squirting, you could just need a full tuneup and carb idle mixture adjustment.

 

[Stuey_15]

Re: Accel problem

Any other ideas? Only because its been into the boat shop already to have a that stuff done an they can't find out what's wrong with it

 

[Don S]

Re: Accel problem

Got an engine serial number. You may just need a new shop. Lots of places know how to throw parts at a problem, but no clue how to troubleshoot a problem.
Was a compression test done? Timing checked properly? Dwell (if you have a points ignition)? Don't guess an answer, that just makes it tougher to find the real problem if you guess wrong.

 

[Stuey_15]

Re: Accel problem

The tune up has been done at 2 shops an it is a new accel pump an the choke is fine new fuel pump new coil new starter motor new plugs an lots more still got me stumped

 

[thumpar]

Re: Accel problem

It sounds like you need to find a shop that will troubleshoot. Are you sure you have a new accelerator pump? That would normally be part of full carb rebuild and not a separate part. Either way you have found 2 shops throwing parts at a problem that has not be diagnosed.

 

[Stuey_15]

Re: Accel problem

I put the new accel pump on myself I keep getting told its a fuel issue but knowone can tell me if its too much or not enough an how to fix it

 

[Maclin]

Re: Accel problem

I certainly do not intend to insult anyone's carby-ed engine knowledge level, but regarding this:
"...I put the new accel pump on myself..."
The way you worded that makes me think you put a new FUEL pump ON the engine. Accelerator pumps are IN the carburetor and are activated mechanically by the carburetor throttle linkage, designed to squirt fuel into the bore as the throttle opens.

Since you are sure the electrical tuneup was complete and good, the symptoms you describe almost certainly emanate from an accelerator pump shot problem, just sayin'.

 

[Don S]

Re: Accel problem

You want answers, but you won't help us help you. We have no idea what vintage engine you have, I asked for a serial number so I could check some things, but no answer.

 

[Stuey_15]

Re: Accel problem

Sorry I only just got the notification I've replaced the fuel pump an the accel pump (plunger) inside the carby and the serial number is m361286 thanks for your help

 

[Stuey_15]

Re: Accel problem

And it is now a electric fuel pump

 

[fishrdan]

Re: Accel problem

And it is now a electric fuel pump

That's a concern, did they also install an oil pressure switch and wire it correctly so the pump only runs when the engine is being cranked or running (has oil pressure).....

Was the the accelerator pump replaced without rebuilding the carb? If so, that's kind of sketchy. Even if it was replaced, that doesn't mean it's working. I replaced the accelerator pump in my carb during rebuild and it stopped working after a week, it swelled up and locked the plunged in the bore (cheap POS part). As Maclin said, with the engine off, have some pump the throttle and see if there are 2 steady streams of fuel that shoot into the carb bores. If it's weak, spitting or nothing comes out, rebuild the carb.

I agree with Maclin, sounds like the accelerator pump. But as Don said, you need to do some troubleshooting, to help us help you. We are no the type of crowd that will advise you to go throwing parts at it without troubleshooting.

 

[Don S]

Re: Accel problem

Check the accelerator pump linkage.