Flooded Carburetor / Choke & Throttle Assy Help

RubioHaz

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Jun 25, 2010
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Boat: 1986 50 H.P. Force (507X6A)

Problem 1: Maxes out at 8 mph.

Problem 2: I've never worked on boats or engines.

Action 1: Read posts, decided might need to clean carburetor.

Action 2: Ordered Clymer manual to find and clean carburetor.


What I need help with:

Cleaned carburetor. The engine still starts but runs for only 5 seconds max now before flooding. Just before it dies, you can see fuel begin to squirt out a hole at the top of the carburetor just about where the idle pin rests. Once it floods the first time, it won't start again (unless you wait for it to evaporate), and a lot of fuel squirts out that same hole. I have uploaded a video showing how the throttle opens the throttle valve, and where the fuel squirts from (http://vimeo.com/12861845 In the video the engine only runs for about 1 second). See picture below.

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The manual arrived yesterday and I took apart and cleaned the carburetor last night with carburetor cleaning fluid (aerosol can). I took off the choke valves at the front (two of them, like a butterfly) and the throttle valve at the back.

I am sure that everything got put back together correctly except for these two valves. The manual doesn't explain how these valves should look, and I can't find pictures anywhere. The top flap of the choke (relieving valve) stays put now because the spring is pushing it toward the back. The bottom flap stays open until the key is pushed in, which makes it shut. See below.

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The throttle valve stays shut until the boat is taken out of neutral and put into forward or reverse. See below.

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I did not replace the gaskets because I don't have them. I can order them if needed but is there anything else I can try in the meantime? The float is empty, clean, level, and moves freely. I unscrewed the nozzle that's underneath the screw that holds the bowl on, but there's a small metal tube that kinds of blocks direct access with a screwdriver to the nozzle. The small metal tube doesn't look like it can be removed and appears to go up through the main chamber, and possibly out the hole that is leaking. Is this some sort of overflow so the fuel doesn't all end up inside the main compression chamber place? I have also tried tightening the idle pin all the way, as well as letting it out more. Still floods.

By the way, there was no washer and no springs inside of the bowl. Parts 16, 22, and 26 in this image. Could these be part of the problem? The float valve and seat (31) also look different than in the manual and the link. I just have a 4-sided pin with a rubber pointy tip at one end which seals the fuel flow off when the float is high enough.
 

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jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
18,196
Re: Flooded Carburetor / Choke & Throttle Assy Help

The idle pin is the air screw.Just bottom it in and turn out 1 full turn.
The leak spot is an overflow for the float bowl.
If the needle valve is not fitting right it will come out there.
If the float is level it might need more of an adjustment to close the needle all the way..The needle/seat sounds like it needs to be replaced.
Most repair kits come with crap in them.I have found using the original is necessary.J
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: Flooded Carburetor / Choke & Throttle Assy Help

The choke plate is assembled incorrectly. You need to take it out and replace the spring so the top half stays parallel with the bottom half both in the open and closed positions. If assembled correctly, when you choke the engine, you should be able to push the top half back with your finger. I forget exactly which way the spring goes but try it. I mean, there are only two ways. It is a little difficult because you must set the spring while setting both halves of the plate on the shaft. If you are ham-handed, let the wife or girlfriend do it--Women generally have better finger dexterity than men. Never did like that choke. Real P.I.T.A.

If fuel is coming out the bowl vent hole (which you indicated) then either the float is stuck in open or down position OR the inlet needle is either missing. stuck open, worn (especially if it has a rubber tip) or the seat is worn. This causes the inlet to not shut and the pump simply fills the entire carb. You need to remove the fuel bowl and check these things. Did you, perhaps, forget to replace the float pivot pin?

Oh, yes. The throttle butterfly plate has beveled edges to match its angle in the carb. These edges are NOT obvious unless you know they are there. It CAN be assembled both ways so check to see that the beveled edges seat flat against the carb case when closed.
 
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