Carb / Fuel Issue

[MPII]

I was wondering if anyone has some tips. I have a 4.3 LX 4bbl weber carb. It runs fine on top end, I get around 4600-4700 rpms, no misses.

The issue is that I can't go from idle to full throttle without easing the throttle up. If you are at idle speed and then hit the throttle, it "falls on its face." It will stall. At first, I thought it was getting too much fuel but now not sure. Fuel is making it into the Carb, fuel pump's working.

Its hard pulling skiers, can't get out of the water fast enough. This winter I am going to take the carb off and rebuild it but I wanted to see if anyone knows what else I should look at?

Any advice is greatly appreciated.

 

[Don S]

Re: Carb / Fuel Issue

Could be the accelerator pump not working up to specs, could be the carb is out of adjustment, or it needs a tuneup.

Here's another post with no clue as to year of boat or engine. Things change year to year guys.

 

[MPII]

Re: Carb / Fuel Issue

Hi Don S. I thought I had it in the signature, I do not. Thanks for the heads up.

Its a 1992 Rinker 206, 4.3 Merc Lx Weber Carb.

 

[Aloysius]

Re: Carb / Fuel Issue

Accelerator pump, or secondary air valve opening too quickly. That big 600 cfm carb has to adjusted spot on to keep up enough airflow through the venturis.

 

[MPII]

Re: Carb / Fuel Issue

So, I wanted to follow up on a post I created last year. At that time, I recently purchased a 1992 Rinker 206 Captiva, Merc. 4.3LX, 4 BBL Webber Carb. At the time I had purchased this Boat. It had sat for 3 years with no use, enclosed in a barn. It is in great shape for its age.

Unfortunately, it had a half tank of old fuel. I drained as much of it as I could and them filled it up with High Test and Fuel/Carb Cleaner. It ran surprisingly well. The only problem was that, if you punched it, it would stall. If you ?eased up? on the throttle, it would do fine.

Many, including on this forum, suggested that I rebuild the Carb and Accel Pump. This I have done. The carb was a mess and it appeared only two of four barrels were functional. Additionally, the choke was not even connected probably.

Put the carb on a few weeks ago and finally took it out last weekend. It starts MUCH easier and seems to idle a lot better.

First Problem, it still is falling on its face off the line.

Second Problem, at 3500 RPMS or more, there is a sort of ?gurgling? or sucking noise but I can?t find any ?vacuum? lines, etc.

Third Problem, (maybe) there are two ?vents? right on the spark arrested and then two hoses that connect. There was steam or smoke, not much, that was emanating from them, Is This Normal?

There is an electric fuel pump on this motor, but, unlike modern motors, no fuel rails as there is a carb. Do I need to pressure test the fuel pump? I don?t really know, not having injectors, if that is possible.

At WOT it seems to run very well, good RPMS, 19 pitch prop 4800, and there are no misses or anything.

Any suggestions would be greatly appreciated.

 

[MPII]

Re: Carb / Fuel Issue

Nothing? Anything?

 

[Bondo]

Re: Carb / Fuel Issue

First Problem, it still is falling on its face off the line.

Second Problem, at 3500 RPMS or more, there is a sort of ?gurgling? or sucking noise but I can?t find any ?vacuum? lines, etc.

Third Problem, (maybe) there are two ?vents? right on the spark arrested and then two hoses that connect. There was steam or smoke, not much, that was emanating from them, Is This Normal?

Ayuh,.... #s 1, 'n 2 are still Carb issues,...
In here is EVERYTHING you could ever want to know 'bout yer Carb...

#3 is just condensation coming outa the oil,... Pretty normal...

The fuelpump should be supplying 4 to 6psi to the carb, but I doubt that's the problem...

 

[snascar2424]

Re: Carb / Fuel Issue

If you have a vacuum leak it could make it fall on its face. try spraying starting fluid around the carb and listen for the rpm's to increase if the rpm's increase you have a leak in that area. The other thing to check is cap,rotor and spark plug gap if you installed new one's make sure the gap is correct some times you will bang a plug just right and close down the gap. The other thing is make sure you check the accel pump for proper operation look in the carb a quickly gas it you should see a stream of gas shoot down the carb. If you don't see a stream you have a plugged up circuit that will need cleaning.

 

[MPII]

Re: Carb / Fuel Issue

Thanks for the tips! I hope I'll be able to figure it out.