1978 mercury 200 20hp missing

[jc_182002]

i have a 1978 mercury 200 20hp that has some issues. When i run the boat at wide open it seems to surge from 3/4 throttle back to full throttle back and forth untill i let out of the throttle. its more like a constant rock front to back while riding in the boat. This motor only does this at wide open. running at any other setting motor runs perfect. Any help will be greatly appericated.

 

[cr2k]

Re: 1978 mercury 200 20hp missing

Check your fuel pump. Try squeezing the primer bulb when it is doing this. If it runs better it is in your fuel system somewhere. Filter, hose leak, filter dirty, pump weak, even the tiny oil routing hoses can be off or bad.

 

[jc_182002]

Re: 1978 mercury 200 20hp missing

thanks i will try this out. Also when you say oil routing hoses, i have noticed right behind the carb there is a small rubber hose maybe 3/16" that runs to the block. This hose is leaking what looks to be fuel. could this be the oil routing hose? I have looked on a couple of exploded views of this motor and cant find it anywhere on the drawings. Thanks

 

[sutor623]

Re: 1978 mercury 200 20hp missing

thanks i will try this out. Also when you say oil routing hoses, i have noticed right behind the carb there is a small rubber hose maybe 3/16" that runs to the block. This hose is leaking what looks to be fuel. could this be the oil routing hose? I have looked on a couple of exploded views of this motor and cant find it anywhere on the drawings. Thanks

Yessir it sure is! I think you've found your problem!!

 

[jc_182002]

Re: 1978 mercury 200 20hp missing

sorry to sound stupid but, does this require any parts to buy or simply replace the hose? as i stated above i can not find any of this info on a diagram.