3.0 litre bogs/slow to get on plane

1216bandit

Petty Officer 1st Class
Joined
Aug 18, 2008
Messages
214
This is on my friends 1991 19' Starcraft Islander. The engine starts great, and idles nicely. After warming up and leaving the dock as the throttle is advanced it will give a snort, bit of a backfire through the carb. The engine runs fine at steady throttle low RPM and great when up on plane at higher RPM, but its that transition area where it really struggles. There is no miss firing or anything else, just really slow to accelerate and pick up rpm's. Does this sound like the choke not fully opening? We will check that and the fuel filter/water separater when we launch tomorrow. Anything else we should look out for? This has only been happening on the last several outings. The motor is fresh less than 50 hrs on the rebuild but the carb was not touched.
Thanx for any tips!
 

Maclin

Admiral
Joined
May 27, 2007
Messages
6,761
Re: 3.0 litre bogs/slow to get on plane

Your description sounds like the accelerator pump in the carb is showing sings of aging. What happens if the throttle is moved forward very slowly up to 3/4 then opened fully? If it does not backfire with that procedure and can get to top speed then it is probably the accel pump in the carb, and would be time to renew the whole carb in my opinion.

Another way to chek the accel pump is, with engine off, move the throttle briskly forward while looking down the carb bores. Two solid streams of fuel should start as soon as the throttle is moved, then dissipate a second or so later. While you are in there, and if the engine is warm (or it is hot outside!) look at the choke plate and linkage and move it some to make sure the choke is not sticking closed.
 

1216bandit

Petty Officer 1st Class
Joined
Aug 18, 2008
Messages
214
Re: 3.0 litre bogs/slow to get on plane

Thank you Maclin for that quick reply! We will check what you have suggested.
 
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