'93 Johnson 25HP RETS won't run below 900RPM

[Tucker99]

Bought this boat 5-weeks ago as an estate sale and engine has never run correct. Good spark, good compression, sync & link to FSM, replaced fuel & water pumps because did not know condition. Same thing, starts but will not idle have to keep wicking throttle to keep above 900 RPM's, lean sneezing the whole time. Rebuild carb, no change. Seems like it is starving for fuel but I have plenty, I can see it in the transparent primer tube. When rebuilding carb, I really couldn't do anything with the lift tube (emulsion tube?) and wondering if there is a problem with that. Is there a source for refurbished carbs, and take mine as a core? Thanks Guys

 

[oldboat1]

Take the carb apart, and soak both halves in solvent -- core plugs out, along with idle needle. Open up all jets before soaking. Try to remove the nozzle after soaking. Finish with carb spray in all openings, along with soft wire.

 

[Tucker99]

Ok, took carb apart soaked overnight replace the plugs. Didn't see any globs of dirt. Made a video, any ideas about the sneez? Thanks Guys...

https://www.youtube.com/watch?v=qbV4Nt5Uw88&feature=youtu.be

 

[racerone]

I am not there to make the quick fix.------Perhaps throttle plate is opening too soon.------Have you tried opening low speed mixture adjustment an 1/8th turn at a time ?

 

[oldboat1]

Usually won't see carb issues. A little fuel varnish from a season ago can cause problems.

Turning the needle clockwise makes for a leaner setting (less fuel, more air). All things being equal, setting too lean gives you a lean sneeze. Try turning counterclockwise about 1/4 turn and see if it runs better. You may be close to a proper setting.

 

[Tucker99]

Thanks, cheez, I thought the needle was an air screw and assumed just the opposite when making adjustments (mental note made). Not sure throttle cable is adjusted correctly. I followed the FSM and threaded the connector onto the housing and adjusted to 1-3/4".

 

[Tucker99]

Thanks, cheez, I thought the needle was an air screw and assumed just the opposite when making adjustments (mental note made). Not sure throttle cable is adjusted correctly. I followed the FSM and threaded the connector onto the housing and adjusted to 1-3/4". Throttle plate opens when the the cam roller is between the hash marks.