Boggs on Acceleration?

fourwinnsdook

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i Have an 86 17ft four winns with a 4.3L in it. It starts right up, But uppon hard acceleration (in the gear only) It will Bogg very bad(stall if i don't let off). If i eas on the throttle it usually does fine. What could it be? It has new plugs, and wires. One thing i did notice is that the choke does not work and the butterfly just flapps around. I am going to try to wire it open. Could this be the problem?
 

wire2

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Jun 25, 2007
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Re: Boggs on Acceleration?

Quite likely. Acceleration means increased air flow thru the carb, which will pull the choke butterfly shut and flood the engine. Is a linkage off or broken? Wiring it open will make it hard to start next time out.
 

fourwinnsdook

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Re: Boggs on Acceleration?

I don't think the choke has worked since i've had it. But the problem seems to be getting worse. I think the problem getting worse has to do with the plugs starting to foul from soo much fuel and not enough air. i;m in he process of a new cap/rotor and new plugs. I also have the carbs apart now for cleaning.
 

Robj

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Re: Boggs on Acceleration?

Sounds like an accelerator pump problem to me. Rebuild the carb which will include replacing the accelerator pump. That should solve your problem.

Have a great day,

Rob.
 

CharlieB

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Apr 10, 2007
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5,617
Re: Boggs on Acceleration?

Check your carb kit!

Merc kit does not include the accel pump plunger!!

It is a seperate part that you NEED to replace.

Sierra kit contains everything.
 

thrasher

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May 23, 2007
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Re: Boggs on Acceleration?

I suspect your accelerator pump is not working. There are two types of accelerator pump used on the 2BBL carb (You don't say which carb you have). If it is the 2BBL carb, you need to open the carb look at the accelerator plunger and then get the Sierra kit with the correct plunger. One plunger has a straight shaft, the other type has a 90 degree bend at the end of the plunger. Otherwise buy both carb kits and return the one you don't use afterwards.

Gary
 

fourwinnsdook

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Re: Boggs on Acceleration?

Ok, UPDATE!!! I rebuilt the carb, installed new distributor cap,rotor, plugs. and plug wires. Problem sill exists. Could it be the points? It's the 2bbl.
 

skeat

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Oct 1, 2007
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Re: Boggs on Acceleration?

did you check to make sure the advance is working properly in the distributor? You can check the accelerator pump by just advancing the throttle and see if gas squirts in the carb
 

fourwinnsdook

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Re: Boggs on Acceleration?

How do i check the timing advance? when i pump the gas it does squirt into the carb but isn't it possible that its not squirting enough? could it be the points? how do i check them?
 

Don S

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Re: Boggs on Acceleration?

Ok, UPDATE!!! I rebuilt the carb, installed new distributor cap,rotor, plugs. and plug wires. Problem sill exists. Could it be the points? It's the 2bbl.

Yes it could be the points. You need new points more often than you do spark plugs. Also replace the condenser.
Then check the point dwell, and once in spec, set the timing.
To check the advance timing, you either need an advance timing light, or look and see how far past 0? it moves.
You can use the timing marks on the tab to determine the distance of 10? then put a mark on the vibration dampner around 30? and see if it goes near it at 3000 rpm.
You also have to have the idle MIXTURE adjusted properly. For it to accelerate smoothly.
 

fourwinnsdook

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Re: Boggs on Acceleration?

before i rebuilt the carbs it was doing the same thing, but when i rebuilt them i set the idle mixture screws back to stock specs. One was already there. and the other was way in. Now that they are both the same i don;t notice much of a difference. Should i move them in or out to try to help the problem?
 

Don S

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Re: Boggs on Acceleration?

Those "Specs" for the idle mixture are nothing more than preliminary adjustmenst to Get It Running for all types of engines. Nothing more.
After the engine is warmed up, they need to be adjusted to fit your engine.
 

fourwinnsdook

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Re: Boggs on Acceleration?

are they always going to be evne or will one side be more turned in or out? it really seems to idle good, the only problem is on WOT take offs. Which way should i try to turn them to improve? Could i be getting too much fuel? It is really acting like to much air.
 

thunderroad

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Re: Boggs on Acceleration?

I know you mentioned you had gas squirting into the throat when you worked the linkage, but was it good, solid streams? Could it be that the notorious check ball under the accelerator pump is missing? I know some carbs didn't have them, but the ones that did will most certainly act just as you're describing if the ball is missing. Some of the the gas that needs to be going into the throat is instead being shoved back into the fuel bowl.
This I know from first hand experience. The ball is about the size of a BB. In fact.....mine IS a BB.
 

fourwinnsdook

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Re: Boggs on Acceleration?

ok, so today before taking the carb back apart and checking the ball i noticed that the accelerator pump arm wasn't fully extended. i also noticed upon disconnecting the arm that it wasn't really squirting untill it got past the part where it was stopping when the throttle linkage was hooked up. i bent the linkage more straight so the the arm gos up farther, and the problem got better, but it still doesn't squirt till towards the top. Could the ball be leaking? It seems like the pump doesn't pressurise very fast. the kit i had did have the balls with it, but i did not replace them. should i run some cleaner through it and see if it helps?
 

Don S

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Re: Boggs on Acceleration?

First off, without knowing what kind of carb you have or how many barrels, or what kind of engine (OMC, Merc, Volvo), a lot of this information is specualtion and general terms.
So, what are you working on?
 

fourwinnsdook

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Re: Boggs on Acceleration?

Sorry, i thought i named that info. It's a 4.3 OMC 2bbl rochester 1986. i think it's called a 2GC, it sais 2 jet on it.
 

Don S

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Re: Boggs on Acceleration?

You don't have a check ball under the accelerator pump on that carb. There should be (and I am using the names as shown in the picture below) A pump spring guide, and a pump discharge spring and the pump ball not pointed out but pictured, that are under the venturi cluster. If it's all corroded up, plugged up, or the spring is broken, or whatever, you will have problems with the way the accelerator pump works.

Full_34048g08.jpg
 

macr6

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Re: Boggs on Acceleration?

When you took the carb apart did you take that ball out? When I rebuilt my carb that little ball was so corroded and gum'd up that it would come out until I "persuaded" it with a plastic toothpic. Once I got it out the bottom of it was gum'd up. It's very hard to see that thing. Good luck
 

fourwinnsdook

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Re: Boggs on Acceleration?

I thought under the pump return spring there was a clip that was holding the ball in... Maybe not. I did see the Pump spring guid, but i did not take it off and replace the ball. I didn't think that had to do with the pump. I am going to try takind the boat out and if the problem continues i will take it back apart and replace the ball.
 
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