Alpha One bog

sogafishin

Cadet
Joined
Jun 14, 2008
Messages
21
I have a 1991 4.3L 2bbl Alpha One that is bogging at WOT.When taking off if I push the throttle wide open the boat will jump up but not plane.I can back off the throttle and it will plane right out.When running I can be cruising about 3200rpm and push to WOT and will actually slow down.I can ease on the throttle and get up to 4400rpm but then push it to WOT and slow down.I can hear the motor bogging.I also feel more pull at half throttle and feel like it falls on its face WOT.Sounds like a carb problem to me but I have no experience with I/Os.Anyone ever run into this problem? Thanks
 

Showtime22

Petty Officer 2nd Class
Joined
Jun 1, 2009
Messages
133
Re: Alpha One bog

Sounds like a carb issue to me, but it also sounds like what my boat did with too small of a prop.

When was the last time the carb was gone thru?
 

WAVENBYE2

Lieutenant Commander
Joined
Apr 28, 2007
Messages
1,636
Re: Alpha One bog

Alpha one is the stern drive(upper&lower unit), 4.3L is the engine, so your engine bogs when you go W.O.T , Ya I agree sounds like carb needs to be adjusted right, have you also checked and adjusted your choke. just did mine yesterday and she flies now:) sounds like it is a simple adjusting and maintaining problem. Hopefully just some simple adjusting.
 

cr2k

Captain
Joined
Mar 19, 2009
Messages
3,730
Re: Alpha One bog

Yep, if yer chock is not opening all the way or your spark arrester is way dirty it will bog.

Other thing to check is your distributors mechanical advance weights. Are they free of rusted in place? Pop the cap off and see if you can turn the rotor back and forth. Should go about 15 degrees or so and be smooth. If not pull the breaker plate and lube them up.
 

sogafishin

Cadet
Joined
Jun 14, 2008
Messages
21
Re: Alpha One bog

I bumped the timing up and nuthing.I have also cleaned the spark arrestor and put on new plug wires.I have just recently purchased the boat so I dont know when the carb was cleaned last.
 

WAVENBYE2

Lieutenant Commander
Joined
Apr 28, 2007
Messages
1,636
Re: Alpha One bog

Are your plugs gapped right, Mine are .35 , i set them at .45 because thats what SELOC manual said and ran like crap, Don S sent me the Mercruiser manual way back when, when it was possable to do so and the correct gap is .35, Guess what I use the SELOC manual for when we go camping, to start fires and does a walk in the woods with out bathrooms come to mind??:D, Are your wires in the right firing order with your distributer cap??
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,097
Re: Alpha One bog

I bumped the timing up and nuthing.I have also cleaned the spark arrestor and put on new plug wires.

Ayuh,... That's all Fine,+ Dandy,....
Now,... Rebuild the Carb,.... That's where your Problem is,..
 

180shabah

Rear Admiral
Joined
Mar 26, 2005
Messages
4,995
Re: Alpha One bog

...and reset the timing to spec before you have new problems.
 

sogafishin

Cadet
Joined
Jun 14, 2008
Messages
21
Re: Alpha One bog

thanks for the replies.I was thinking it was starving for gas this whole time,Wanted to cover all areas before I took the carb off and rebuilt it.I have a buddy with a 5.0L the he put a 4bbl intake and carb on.He still has his 2bbl set up.His boat was running perfect with the old 2bbl.Will that carb bolt on the 4.3 manifold?It would get me thru the weekend while I was working on my carb.
 
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