Logo
FULL SITE MENU

84 70hp bogging

S

scalhoun506

Regular Contributor
this story been told before i'm sure, (engine new to me) idles good, push throttle and gets to 33-3500 rps then bogs, bump key in and zoom for a few seconds, then back to 3500
backround info - carbs rebuilt w/kits, have online manual, cam roller lined up with lower mark on cam(2 on cam), spark advance moving to stop when throttle advanced, did drop test at idle , rpm drops on all cylinders, get cheap china fuel pump would't pull fuel at idle had to keep pumping bulb every minute or two, back to old pump, think compression is 130, was when bought
next will compression check again, and check high speed jets( will remove drain screw and poke wire throw), looking for suggestions for next weekends work list.
 
no jets were not removed, reamed out with welders torch tip cleaners, a couple of pokes nothing ruff and of course break cleaner spray, I've damaged jets before, they tend to be very tight.

and racerone, is there a procedure to test that possibility? or just order gaskets and go for it
 
scalhoun506 said:
no jets were not removed, reamed out with welders torch tip cleaners, a couple of pokes nothing ruff and of course break cleaner spray, I've damaged jets before, they tend to be very tight.

and racerone, is there a procedure to test that possibility? or just order gaskets and go for it
Click to expand...

Did you replace the float? If so, it needs to be adjusted to allow the bowl to fill enough to sustain power at speed.
 
yes replaced, adjusted float to level or just a hair raised when carb body upside down. didn't adjust the float drop. manual says between 1 1/8 - 1 5/8, an 1/2 in span, didn't think it was that critical measurement being that large, but thinking about it that's what opens needle valve, will address on second cleaning, guess the smaller measurement would let fuel in sooner, thanks for suggestion, may be awhile before getting into it, rock fish season open in VA, got 33 in. last weekend(second boat)
 
Check the needle while you're at it. Mine was rubber and was sticking in the seat. Replaced it with a new seat and needle which is all metal.
 
update: yep at least one high speed jet clogged, reset floats to level with carb body and set float drop within 1/2 inch range from setting in manual. and installed CCMS reeds with stuffers. BOOM, takes off great, no hesitation, maxes out about 52-5300 rpms. will do lower unit maintenance and water pump soon
tach is jumping around at idle, but steady at cruise, hope stator not getting ready to go out
noted temp around 145-150 at idle but 155-160 at cruise, in previous post changed thermostat, pressure relief valves and springs new springs were definitely stronger and different size, and 2 of them on this engine, thinking about putting one old one back in, but will evaluate with new impeller installed
 
Back
Top