Possible carb issue or normal?

[Chuckles88]

89' 4.3 with a 2b carb. At idle on muffs runs rich. I'm at 4200'. I trolled for 10-15 minutes and went to relocate but it was flooded out. Ran it up to wot to clean it out and ran fine the rest of the day. New carb time? Rebuild? Switch to a 4b or is it worth it? Or leave it alone. I won't be trolling again with this set up. Thanks!

 

[harringtondav]

I'm guessing here, 'cause I don't know your boat's history. Like when was your carb last rebuilt, and is this a new problem? Many things can cause a rich mixture. Dirty clogged spark arrester, worn float needle needle, dirty carb preventing proper air bleed mixture. I'd start with a good immersion soak of the carb body and air horn, compressed air blow out of all passages, especially the tiny transition (progression achris) passages just below the throttle plates , then a kit. Clean your spark arrester in mineral spirits (low odor paint thinner) and blow it out from the inside. Mind the float height setting per the instructions or manual if you have one.

Before you disassemble, be sure to count the exact turns on your idle mixture screw(s) to seat, and set them back to this as a starting point.

It's a fairly cheap first try in terms of $$ and your time. Good luck.

 

[Chuckles88]

I'm not to sure on the history of the boat but I have had it out a dozen times and it has been rich since day one. The carb appears to be original after looking at bolts and screws that don't appear to have been turned. It smells like raw fuel from the exhaust pretty bad until it has been ran for a while and then it is tolerable. I have cleaned the arrestor along with new plugs, wires, cap and rotor.

 

[achris]

I'm not to sure on the history of the boat ....

Then you should be doing a full service to get yourself a 'baseline.

Especially check compressions and timing.

Once you know those are good, start looking at other things. If you're smelling petrol, then you have unburnt fuel somewhere, probably just a rich idle mixture on the carb. But, as you don't know the history, time to strip and clean and reset all the adjustments.

I wouldn't bother with a 4bbl just yet.

Chris......

 

[Chuckles88]

I have checked everything but the carb and compression. The old plugs looked the same- carboned and consistent. Idle adjustments are for just that right? Not for anything past idle?

 

[AShipShow]

Correct, idle screw only affects low rpm. I would also suggest you rebuild the carb.. pretty easy job and can be done in an afternoon. Even if that doesn't fix it, it's a good idea to do it since you don't know the history.

if you're interested, the link in my signature will take you to a thread with 3 videos I did on the whole process for your mercarb...

 

[wahlejim]

You may also want to check that your choke isn't sticking closed. With that being said, I agree with the other advice. Get a baseline for compression, timing, and rebuild your carb.

 

[Chuckles88]

Thanks!