carb rebuild?

[steve5]

I have a 2000 4.3 GL. Last year I noticed some black soot on back of boat after an afternoon being on the water. The engine runs well exhaust does smell a little rich. Carb looks like it has never been rebuilt there are no witness marks in the paint on the screws like they have never been removed. Is it normal to see some residue after running engine for 3-4 hours? I have rebuilt several Quadra jet carbs but never a holley. Is the holley that difficult to rebuild?

 

[Augoose]

Re: carb rebuild?

I have a 2000 4.3 GL. Last year I noticed some black soot on back of boat after an afternoon being on the water. The engine runs well exhaust does smell a little rich. Carb looks like it has never been rebuilt there are no witness marks in the paint on the screws like they have never been removed. Is it normal to see some residue after running engine for 3-4 hours? I have rebuilt several Quadra jet carbs but never a holley. Is the holley that difficult to rebuild?

I'd say no, residue after running is not normal. Where was the soot?
Start with pulling the plugs and see what they look like - maybe even post a photo of them so we can give input.
If you can rebuild the Rochester quadra's, IMO the Holley's are even easier. I can't recall the exact process I had to go through to order the correct rebuild kit, but if you start with Volvo's website and look up your carb model number, that'll head you off in the right direction.

The other thing I'd add is that you are either getting too much fuel or not enough air. Is the flame arrestor clogged? Has it been cleaned? Open the butterfly and look down the throat of the carb while you give the throttle a good pump (engine off). Do you see a dribble or a good strong squirt of fuel?
Do you have an automatic choke? Did it come out of adjustment? When the engine is warmed up fully, are the butterfly's all the way open?

 

[insttech1]

Re: carb rebuild?

If that carb hasn't been touched in 13 years, I would think it's definitely time to go through it.
The rebuild kits come with good instructions (for the most part).
You just have to ensure that you get the right marine kit, and make sure it's from Holley, and not Sierra, etc...
Also make sure you get the one with the exact same diaphram pump, and power valve.

The right kit will contain all new gaskets, and even extras that you don't need. Pay special attention to those gaskets, as there are some very tiny ports cut out that are critical if you block them off w/ the wrong gasket. Just lay old over new to see which ones you will need, and which to set aside, and which way they actually go on the part....some are not reversible.

I would carefully note the location of the float before removing the needle/seat for replacement.
Holley's definition for a "center hung" and "parallel to the bowl" float leaves a lot of wiggle room for interpretation, especially when there are four or five flat surfaces on the float, and calling their help line was less than.......helpful.

But overall the rebuild is pretty easy. Just take pic's with your phone during each step in case you have a "where did that go?" moment during re-assembly.

 

[SteveMcD]

Re: carb rebuild?

I'm not a carb expert, so I sent mine back to Holley. They rebuild.

 

[cr2k]

Re: carb rebuild?

Also contributing to "rich" running and or soot on the back is plugged exhaust manifolds.

 

[Tail_Gunner]

Re: carb rebuild?

..marine engine's run very rich.....read very. Check your plug's for the correct heat range....a 160 thermostat wrong plugs or a cold thermostat will soot things up. You can probably buy a edelbrock 1409 for cheap if you must..I mean it is 14 yrs old and it's not going to meter to tight anymore.