4.3 runs great for about 30 minutes then bogs, pops won't accelerate

[coolbucket]

Replaced TKS carb with new correct electric choke carb. New fuel/ water filter, timing good, drained old gas filled with non-ethanol. Starts and runs great for 30 minutes then pops and bogs. Will idle but won't accelerate. Can put it in neutral and it revs fine. Any help????

 

[coolbucket]

I put in New spark plugs also.

 

[coolbucket]

I ran at 30 mph for 30 minutes yesterday, ran great! Then started popping and bogged. Would idle and go into gear but no acceleration.

 

[Scott06]

I ran at 30 mph for 30 minutes yesterday, ran great! Then started popping and bogged. Would idle and go into gear but no acceleration.

Try opening the fuel tank fill cap to see if the fuel tank is under vaccum due to a plugged vent.

Did this start immediately when swapping the carb or were you having carb issues before swapping the carb?

reving in neutral is relatively meaning less as the engine is not under load. Do you have a good spark when this happens? Maybe test spark with spark gap tester. Is coil hot when this happens?

 

[coolbucket]

The mechanic's taking out on the water to do diagnostics. I guess I'll find out what the result will be by the end of the day. I can't keep guessing. No, the problem was before I exchange the carburetor.

 

[drryan]

I had a similar problem and a mechanic suggested replacing the coil. Cured my issues. Before I felt it was a fuel issue also.

 

[Scott Danforth]

I had a similar problem and a mechanic suggested replacing the coil. Cured my issues. Before I felt it was a fuel issue also.

It's never the coil

 

[dubs283]

Someone from my past who's forgotten more about outboard motors that i could ever learn once told me "there's no nevers or always with boats"

Sometimes it's the coil, rare yes. But sometimes

It doesn't hurt anything to install a new, proper coil.

 

[coolbucket]

It's never the coil

Never say never.

 

[coolbucket]

It was my coil Scott.

 

[coolbucket]

Boat runs great for 30 minutes then pops and bogs. Won't accelerate above idle. My mechanic has figured the carb timing was not done right. Here's what a member said. Is he right that this should remedy my issue?
You need to put it in base mode before setting the timing to 10 BTDC.Just look for the timing base mode bullet connector just to the left of the carb. Ground it before you turn on the engine it prevents the adavance from kicking in so you can set initial timing.

 

[coolbucket]

I have spent the last month listening to a people's opinions on this site about how to remedy my problem with my Mercruiser 4.3 l engine. I've gone through the electrical, the gas, and carbonation suspects...zip. Not until today did the Mercruiser folks inform me that my engine must use a jumper while timing this engine. If you don't use the jumper the engine reverts to base. Hence you get the popping and big issues I've had. Not one so called expert mentioned this. Now you know, pass it on to the next poor sap hoping for some help here.

 

[alldodge]

I merged your 3 threads because they are all about the same thing

 

[brodmann]

In my old "hot rod" days, the first thing we would do if this happened was to check to see if the coil was hot to the touch. If it was we replaced it. We would occasionally test for resistance on the coil, but usually just toss it and replace it. The older guys would shake it to see if it sounded like it had fluid in it. If it did, they said "the insulator in it had broken down or melted".

 

[coolbucket]

It was the timing. On the 4.3 mercruiser you have to use a jumper on the distributer to clear the base timing. Regular old school timing won't work on this engine. Problem solved!!!

 

[alldodge]

It was the timing. On the 4.3 mercruiser you have to use a jumper on the distributer to clear the base timing. Regular old school timing won't work on this engine. Problem solved!!!

The jumper doesn't "clear" base timing, it puts it in base timing mode so it can be timed.

 

[1985 Century Mustang]

The jumper doesn't "clear" base timing, it puts it in base timing mode so it can be timed.

Interesting!

 

[coolbucket]

Interesting!

Whatever.It fixed a problem nobody on this forum could come up with.

 

[Bondo]

It was my coil Scott.

It was the timing. On the 4.3 mercruiser you have to use a jumper on the distributer to clear the base timing. Regular old school timing won't work on this engine. Problem solved!!!

Whatever. It fixed a problem nobody on this forum could come up with. I think it's a bunch of shade tree mechanics bouncing off possibilities on this site. Not for me.

Ayuh,..... Sorry,..... Have a nice life,.....
Yer at 2 Cures at this point,..... 'n I'm guessin' it ain't over yet,....

What was the timing set at,..??

'n nowhere in yer 3 different threads(a violation of the posting rules, 'n guidelines), about the same problem, did you offer the vintage of the motor, nor a serial number,.....

 

[dubs283]

Whatever.It fixed a problem nobody on this forum could come up with.

But....

People helping on this forum didn't "come up with the problem", your engine did and you posted?

Is it okay that I'm confused reading this thread?