Engine won't fully rev up

[trobinson017]

I recently had my '99 Johnson 130 Oceanpro worked on wherein all 4 carbs were replaced and the VRO was inspected. Due to the fuel in the tank being fouled pretty badly I've been running with an external 6.5 gal tank. 2 weeks ago I ran it WOT for about 7 minutes, then at slow speeds for about 30 mins, then another 7 min. WOT. During the last WOT period the motor revved down about halfway even tho the throttle was still wide open. I coulnd't get it to planing speed after that. I brought it home and looked the engine over. Nothing appeared out of the ordinary. There was oil in the fuel from the oil injection system so that was a relief. Yesterday I took it out and it started to fully rev, then dropped, then started to try and rev up but it couldn't. I thought something might be up with the oil injection system so I put some oil directly into the external tank. That didn't help. I still couldn't get the engine to rev up fully, not even enough to get onto plane. Fuel flows fine up to where it enters the fuel pump. The filter looks clean, nothing's clogging it up. The bulb is new too so no disintegration bits are getting into the line. I just can't figure out why it's not revving up to planing speed and beyond.

Any ideas?

 

[Jggrmson]

Re: Engine won't fully rev up

im kinda a noob at OB repairs but...check the compression and spark first. then check the carbs. sounds like they are dirty. carb cleaner + compressed air will work wonders. hope it helps.

 

[tashasdaddy]

Re: Engine won't fully rev up

are you using a 5/16 fuel line or a 3/8 fuel line on the portable tank? check you spark and compression, if good go to a 3/8 hose on the fuel tank, and loosen the fill cap, may not be getting enough vent. if it still messes up, i would look at contaminated carbs.