80s mercury 9.8 trolling speed issue

[Craigmail361]

I have a 9.8, sometime from the 80s, starts awesome, idles in neutral all day, really quick off the line and holds out at WOT all day. Once I go anywhere near trolling speeds (fwd under load,low rpm) it tends to try to bog down and die, I really have to keep on the gas. Plugs are new, I'm assuming carbs clean from what the previous owner said, everything tight, new fuel and lines, A/F adjusted perfect from what I know. 50:1 ratio for fuel. I'm assuming I have to take apart the carb again cause that's the only possible thing I think it could be, not sure if I trust the other guys work, bought it a few months ago and take it out every weekend. Thanks

 

[Scott Danforth]

check the carb. easy carb to clean

maybe drop the prop down a pitch and raise the idle speed.

 

[racerone]

???----There could be a lot of things wrong !----Test cylinder compression first.----Could be a reed valve problem resulting in low crankcase compression.----Could be the top or bottom crankshaft seal too.-----Have you installed a new water pump impeller ?

 

[Craigmail361]

Well I cleaned the carb and ran it at home and ran great and steady in fwd gear all day, took out on the lake next day and it was hesitating and running like crap the first 30 minutes but smoothed out for the rest of the day, it stalled maybe 2 times at low rpm and I couldn't hit my plane speed at all, running like a dog. New impeller, carbs clean, new plugs, strained cleaned with new tank, primer bulb and lines, and fresh 50:1 ratio of gas/oil, stuck stuck stuck need advice

 

[racerone]

Is it firing on both cylinders , yes or no ?

 

[Craigmail361]

I will double check, but I thought for sure a week ago when I swapped plugs they were great!

 

[racerone]

???-----Not sure what you mean with post # 6-----Is the motor running on both cylinders , yes or no ?----Will it start with top plug wire off, yes or no ?----Will it start with just the bottom wire off, yes or no ?

 

[Craigmail361]

Sorry yes it will