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Hesitation at throttle up merc 470

D

dlux

Member
"I've done a recent tune u

"I've done a recent tune up on my 86 Glasply w/a 470 merc and I cant seem to eliminate a hesitation at normal acceleration, if I put it down a little harder it will recover and take off at a quick pace but the wife doesn't care for that too much. Any thoughts."
 
Does it have a points ignition

Does it have a points ignition? Yes? Check for rust on the advance weights.
 
"Thank you both for the respon

"Thank you both for the response, I did a recent carb rebuild with a sierra kit, I have read about that problem with the accelarator pump, I'll have to take another look at that,I will check the advance weights, would going to an electronic ignition help out?"
 
"If the accelarator pump is ad

"If the accelarator pump is adjustable, try the next upper position for a longer pump stroke.

Electronic ignition conversions provide a consistent spark w/o the changes caused by points wearing down. Timing also stays consistent.

I changed out my 10 yr. old merc. coil that was working for a Blaster high vibration coil; filled w/epoxy and not oil. I feel the engine runs slightly better w/a hotter spark. I too have the accelerator pump hesitation when moving the throttle slowly; it's the nature of the Merc. 2 BBL carb. I'll give it a set of new plugs and adjust the mixture w/a vacuum gauge this fall. It's time for it as a PM item."
 
Guys;
I am no expert on the 2

Guys;
I am no expert on the 2 bbl Mercarb (since I have never owned one) but I seem to remember a post not long ago about this problem. I recall that it had something to do with a check ball that is usually missing at the bottom of the accelerator pump bore.
Don't know if that will help or hinder; just a thought.

Rod
 
Rod:

The carb is a reman. M

Rod:

The carb is a reman. Merc. so I don't know if it has a check ball since it has not been rebuilt by me yet; will check it though--big thanks.

MistaHays:

"rusty advance weights theory" Seen it on auto dist. years ago. Somebody mentioned it this past year or so. Just a repeating their find and fix. How's the cruiser?
 
Does the hesitation happen whe

Does the hesitation happen when it's cold or warmed up or both? Is there no difference between warm and cold? I had to adjust the idle air mix on mine. It ran great when it was cold but when warmed up and running for a while it would hesitate and not want to idle very smooth. I took it out on the lake for an hour of cruising to make sure it was well warmed up and adjusted the two idle air screws one at a time. The engine was running way too rich before which caused it to run rough at low RPMS. It runs great now warm or cold with no hesititions.
 
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