Pontoon Boat & Deck Boat Forum

Newbie I have 1989 70 hp johnson runs good until T push throttle
down engine starts hesitating and feels like it will stall any help please

Are you running with fresh fuel?

Is your fuel vent open?

Fresh fuel, fuel vent, check filters, check fuel lines and bulb. Check end of siphon tube in fuel tank. Is fuel good? May need fuel pump rubber membrane and/or carb. cleaning.

Also, when in doubt, change the plugs. Sometimes new plugs can do wonders.

Ron Burgundy wrote:Are you running with fresh fuel?

yes I will check to see if my fuel vent is open Thank you

Take a real close look at the clip on fuel fittings its real common for those to wear and suck air.

one word......CARBS!

Classic dirty carb symptom.

In gear or neutral?

Bryden24shp wrote:In gear or neutral?

in gear

Could be a lower unit problem, too. You may be getting a galled thrust bearing. Does everything spin freely in neutral, with the engine shut off? If yes, then I would say, pull the carbs, cause they will really act up more under a load. But check the obvious, first. Pull a little sample of the lower unit oil and see if it looks clean or metallicly. (Is that a word?)
Let us know what you find!

Agreed on the dirty carb, probably a gummed up float needle, but while you've got them out do yourself a favor and rebuild them instead of just clean them. For about $30.00 per kit it's cheap insurance that they'll all be happy for several more years. I mean, 'ya gotta take 'em apart anyway. Go buy a selection of guitar strings - they are perfect for reaming out gummed up passage ways without disturbing the bore. Then shoot some Berryman carb cleaner through each one to remove any final residue, gently blow compressed air through them.

When you hear hoof beats don't go looking for zebras.

RonKMiller wrote:Agreed on the dirty carb, probably a gummed up float needle, but while you've got them out do yourself a favor and rebuild them instead of just clean them. For about $30.00 per kit it's cheap insurance that they'll all be happy for several more years. I mean, 'ya gotta take 'em apart anyway. Go buy a selection of guitar strings - they are perfect for reaming out gummed up passage ways without disturbing the bore. Then shoot some Berryman carb cleaner through each one to remove any final residue, gently blow compressed air through them.

When you hear hoof beats don't go looking for zebras.

or speaker wire is what use.

Thanks I believe it was the fuel vent. Thanks again