1984 SN 2001 - Holly Carb

First thing I'd do would be to call Holley tech support with the list number from the airhorn. That number will be able to tell them what the carb is. If you find that it is a 351 Ford marine carb they can tell you what rebuild kit number you need. Ask them what size jets are supposed to be in it. Get the kit and a 6.5 power valve to replace the one sent in the kit. Some kits do not have the secondary diaphram so ask that too and get one if you need it.Pull it apart,clean it and reassemble it. If it isn't a marine carb,ditch it and get a new one.

It probably will need a rebuild, but that doesn't mean it needs to be done pronto. First thing I would do would be turn the idle screws on the primary(front) bowl in all the way(gently). Then back them out 1.5 turns. Then I would start her up and pull the view plug out to make sure your bowl level is set correctly(if you have one it is the plug on the front bowl starboard side). You want it just below the bottom of the hole, maybe even dead even with the bottom of the hole depending on how level the engine is.

As far as a rebuild kit, as indicated pull the #s off the front of your carb at the base of the airhat, then call holley. Most of holley's newere kits include a base gasket and secondary diaphram now. You can ask the tech rep which pv it will come with as it depends on your model. Most of their marine kits come with a 2.5, but a few of their newer style kits come with a 5.0(mine did). None I'm aware of come with a 6.5(part # 125-65), so you'd need to order that additionally if you decided you needed it. 2.5 will work just fine, however a lot of people on here have seen positive results in mid throttle response with the larger # PV. Its in the front metering block and takes about 2 minutes to get to, so don't think you have to make a decision to go with a 6.5 now. You can always swap it later. Most on here would suggest you stick with a holley brand kit. Cheapest I've found lately has been through summitracing who also carry the power valves and extra gaskets for cheap. Since you should probably do a tune up as well they also happen to have the cheapest price on the autolite 764s I've seen.

The smell of raw fuel is very strong when running. Especially from the back of the boat. Also the boat vibrates more than it should at idle and the engine seems to lope. Engine runs and sounds normal at higher rpm.

n5891e wrote: The smell of raw fuel is very strong when running. Especially from the back of the boat. Also the boat vibrates more than it should at idle and the engine seems to lope. Engine runs and sounds normal at higher rpm.

It probably is a carb setting but it can't hurt to make sure your fuel tank vent is actually connected to the fitting on the hull and not pumping fuel vapors in the boat. If it fell off, the fuel vapors would be really bad at the back of the boat too.

thats your accel pump shooting a stream when you juice the throttle, which is what its supposed to do. Nut makes another good point. Seems you have some settings to check and a vent to check before we can help you any further. Let us know, carbs are simple, but finacky, creatures.

Ok. Still working on the possibility of a re build. Today under cold engine condition I removed the rubber cap from the vacuum stud picture below. About a table spoon of fuel poured out. Ok. Can't figure out how to post image.