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Mercury 4.3 alpha 1 drive stalls during excelleratipn

R

Ravgardner

New member
Purchased this 2014 bow rider used and it came with water in the gas and ethanol related carb corrosion. Had the carb rebuilt. Still didn’t idle or run well. Mechanic enriched the mixture some which has cured most trouble, except the stalling during excelleration. The exceratation pump has three holes to that you can attach the throttle rod too. It’s currently in the. Middle hole. Could changing the position of the rod increase the effectiveness of the execration pump?

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Did you try to run engine off of an auxiliary tank and hose plumbed to engine, completely separate from existing, with known good fuel?
 
noelct said:
Did you try to run engine off of an auxiliary tank and hose plumbed to engine, completely separate from existing, with known good fuel?
Click to expand...

We siphoned the tank empty. Have used non ethanol fuel in it since. Pulls good once it’s above 1800 or 2000 rpm.
 
Ravgardner said:
Purchased this 2014 bow rider used and it came with water in the gas and ethanol related carb corrosion. Had the carb rebuilt. Still didn’t idle or run well. Mechanic enriched the mixture some which has cured most trouble, except the stalling during excelleration. The exceratation pump has three holes to that you can attach the throttle rod too. It’s currently in the. Middle hole. Could changing the position of the rod increase the effectiveness of the execration pump?

e229fdc7-d8cc-4aa5-b6d7-bbe89f4613c5
Click to expand...

Ayuh,.... Try goin' to the richer hole on the rod,....
 
The hole closest to the pivot point on the acceleration pump will increase the stroke. On the other side, the throttle arm side, some carbs have adjustment holes there too. On that side, to increase fuel blast, then we move to a hole FARTHER from the pivot point. As o2 states, there could be another issue, perhaps related to timing advance. What did the mechanic do to "richen" the fuel/air mixture?
 
Ravgardner said:
Which hole is the richer one? The upper one near the air intake or the lowest one? It’s in the middle now.
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The upper one is the biggest shot volume. Also make sure it moves freely and that the rod that connects to the throttle linkage has no slack in it. the pump lever should have some pressure pushing back against the linkage rod, if not bend it longer.

If you have some slop in the linkage it can cause a delay in the pump shot and a momentary bog....
 
Who ever you paid to rebuild the carb and if the same "mechanic" who adjusted the idle mixtire. Have them resolve your issue.
There is no need for you to figure this out if you didnt do any of the repairs/rebuild
 
timguy said:
The hole closest to the pivot point on the acceleration pump will increase the stroke. On the other side, the throttle arm side, some carbs have adjustment holes there too. On that side, to increase fuel blast, then we move to a hole FARTHER from the pivot point. As o2 states, there could be another issue, perhaps related to timing advance. What did the mechanic do to "richen" the fuel/air mixture?
Click to expand...

The mechanic removed a plug and turned a screw with a screw driver to change the fuel mixture. Hope you will know what the screw was.
 
kghost said:
Who ever you paid to rebuild the carb and if the same "mechanic" who adjusted the idle mixtire. Have them resolve your issue.
There is no need for you to figure this out if you didnt do any of the repairs/rebuild
Click to expand...

i’d would like to do that, but he is out of the business now. I’m on my own.
 
It is rare to have to change the accelerator pump linkage location on a stock OEM 4.3.

First you need to identify by taking cover and flame arrestor off, looking into carb,
See if, when you move throttle lever, gas squirts.
It must squirt immediatly when throttle lever is moved. The duration of the squirt is not as critical but should allow a fair amount of gas to be squirted.

If you do not have has squirting as soon as throttle is moved.
Then and Maybe changing the pump lever hole might work.

Report back about gas squirting or not at exact same time throttle lever is moved.

Note: Take keys out of ignition for this test!! No cranking with flame arrestor removed!
 
kghost said:
It is rare to have to change the accelerator pump linkage location on a stock OEM 4.3.

First you need to identify by taking cover and flame arrestor off, looking into carb,
See if, when you move throttle lever, gas squirts.
It must squirt immediatly when throttle lever is moved. The duration of the squirt is not as critical but should allow a fair amount of gas to be squirted.

If you do not have has squirting as soon as throttle is moved.
Then and Maybe changing the pump lever hole might work.

Report back about gas squirting or not at exact same time throttle lever is moved.

Note: Take keys out of ignition for this test!! No cranking with flame arrestor removed!
Click to expand...

Got a friend over to help check the recommended functions. The arm of the excelleration pump moves when it should, I think. A good squirt of gas results from both jets. So I think it passed those tests.
 
It is not just that it quirts, it is the timing of the squirt.
It must squirt exactly when the throttle lever moves.

If the throttle lever moves, say 1/2 inch of rotation and no squirt then that is an issue.
.
So confrim the timing of the squirt. Not the fact it squirts.
 
kghost said:
It is not just that it quirts, it is the timing of the squirt.
It must squirt exactly when the throttle lever moves.

If the throttle lever moves, say 1/2 inch of rotation and no squirt then that is an issue.
.
So confrim the timing of the squirt. Not the fact it squirts.
Click to expand...

ill recheck with that in mind. Thanks for. The help.
 
The excelleration pump seems to be timed well with the throttle.
I’ve run two tanks of fuel through containing Sea foam SF-16. Much to my surprise, the engine seems to be excellerating better. May is wishful delusion on my part, but I’ll have try it some more to be sure.

thansk so much for all the suggestions. This is a most helpful group. If you have any more ideas please share them.
 
Cable is not your issue and could not be.

Based on your last post, you have/had bad gas and bad carb caused by bad gas.

This is very common with boats.

Had the same issue with a boat 3 weeks ago.
Bad crappy gas took the carb out. Rebuilt card, new water seperating filter, flushed gas tank and replaced old antireversion fitting at tank.
 
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