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Need your help! Engine bogging while accelerating

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Old 07-21-2016 | 07:55 AM
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Default Need your help! Engine bogging while accelerating

Hey guys I have a 1994 wellcraft scarab 22 with a 350 merc small block. I already posted about this before and appreciate that feedback. While planning out you can feel/hear the engine hesitate then Pick back up. I already replaced the fuel filter. Seemed better for sure but still some hesitation. The last couple times I have noticed when I really throttle down I can hear/feel telhe hesitation at higher speeds/rpm but if I am just cruising it runs perfectly. Really want to get this engine running properly as I just bought the boat recently. It was sitting for a little while before I bought it. All in all it runs fine but I would be much happier if it planned out easily and ran solid at high speed.

Appreciate your help.

-Tim
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Old 07-21-2016 | 08:31 AM
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Have the carb rebuilt. Cheap and given the age of the boat it wouldn't hurt anyway. If you have all the old fuel out and a new filter then most likely it is an accelerator pump issue. A full tune-up should be on your to-do list as well if you cannot verify age of parts. Cap, rotor, wires, plugs.
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Old 07-21-2016 | 09:11 AM
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Originally Posted by Knot 4 Me
Have the carb rebuilt. Cheap and given the age of the boat it wouldn't hurt anyway. If you have all the old fuel out and a new filter then most likely it is an accelerator pump issue. A full tune-up should be on your to-do list as well if you cannot verify age of parts. Cap, rotor, wires, plugs.
Thank you for the quick response that's what I figured. From you experience how much is a full tune typically going to cost me?

Thanks,

Tim
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Old 07-21-2016 | 10:36 AM
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i wouldn't worry about the tune-up at the moment. I always do my own wrenching so for me the cost is parts only and it is fairly inexpensive.
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Old 07-21-2016 | 10:51 AM
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Originally Posted by Knot 4 Me
i wouldn't worry about the tune-up at the moment. I always do my own wrenching so for me the cost is parts only and it is fairly inexpensive.
So for now my main priority should be to rebuild the carb? You think that's probably the issue?
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Old 07-21-2016 | 10:56 AM
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Could be fuel.
Could be plugs and/or cap and rotor and/or wires
Could be carb's choke staying closed or varnish/e10 crud in carb

Can you do any work on your own ?
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Old 07-21-2016 | 11:06 AM
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Originally Posted by SB
Could be fuel.
Could be plugs and/or cap and rotor and/or wires
Could be carb's choke staying closed or varnish/e10 crud in carb

Can you do any work on your own ?
I have people who can help me for sure so yes I prefer to not pay the marina. What do you suggest I do to start? I will do as much as I can.

-Tim
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Old 07-21-2016 | 11:16 AM
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If carbureted, Ck choke to see if fully opening. Should be within 2 minutes or so after engine is started.

Since you have to take off flame arrestor to do this, bring flame arrestor in and scrub out fins with water and dawn diswahing liquid. No one cleans these for some reason and they should.

Look at ignition wires. If Merc, the last two #'s are the year made. Q94 will be 1994. Q16 will be 2016 and etc,etc

Unscrew cap and take a look inside. Be careful, the hold down screws will fall out when cap turned over, so remove them before you do so.

Pull one or two spark plugs. Take a look to see if worn. As a heads up, most spark plug sockets won't clear the factory exhaust manifolds. You'll need a very thin wall deep socket vs a normal spark plug socket. Plugs are normally 5/8".

How long has boat sat ?
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Old 07-21-2016 | 12:22 PM
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Originally Posted by SB
If carbureted, Ck choke to see if fully opening. Should be within 2 minutes or so after engine is started.

Since you have to take off flame arrestor to do this, bring flame arrestor in and scrub out fins with water and dawn diswahing liquid. No one cleans these for some reason and they should.

Look at ignition wires. If Merc, the last two #'s are the year made. Q94 will be 1994. Q16 will be 2016 and etc,etc

Unscrew cap and take a look inside. Be careful, the hold down screws will fall out when cap turned over, so remove them before you do so.

Pull one or two spark plugs. Take a look to see if worn. As a heads up, most spark plug sockets won't clear the factory exhaust manifolds. You'll need a very thin wall deep socket vs a normal spark plug socket. Plugs are normally 5/8".

How long has boat sat ?
Excellent thanks for all of that its a huge help. My understanding is it was "sitting" the last couple seasons. The owner did run the boat here and there just not as much as years prior. It's in great shape but it definitely needs some engine love haha.
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Old 07-21-2016 | 01:14 PM
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If you do not have thru hull exhaust (like many small blocks), then check to see if your flappers are intact in the top of the Y pipe. These flappers when they break loose will normally find their way into the drive, but sometimes will stay lodged in the Y pipe...where ever the flappers end up, they obstruct the exhaust flow and will cause a hesitation UNDER LOAD and shave off varying amounts of top speed. This is something that often gets overlooked on older boats and has confounded many a mechanic.
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