50hp Force has low rpms in gear

Hello. My brother in-law has a 1986 Force 50hp outboard on a 14' Bayliner. He bought the boat a few months ago. He had a marina change the water pump and clean/adjust the carb. The boat ran really well until just recently. I replaced the rectifier since it tested bad and he was getting no battery charge. I also cleaned up all the wire connections since they were oxidized and fixed his throttle handle that the screw had backed out from. Now the boat will not go over 6 or 7 mph. In reverse or neutral the engine reaches top rpms since there is no real"drag" on the engine, but in forward gear the rpms stay very low. I detached the throttle and shift cables at the engine and manually shifted into gear. Then I opened the throttle plate up right at the cam. Still no rpms. I checked to be sure I have spark on both cylinders and I do. Any thoughts?

The revving up with a no load situation is normal.
Is the throttle advancing the trigger base as you push the throttle forward?
The carb, the throttle plate going flat or close to flat when at full throttle?
Do a compression test.

Jerryjerry05 said:

The revving up with a no load situation is normal.
Is the throttle advancing the trigger base as you push the throttle forward?
The carb, the throttle plate going flat or close to flat when at full throttle?
Do a compression test.

Click to expand...

Jerry,
thank you for getting back to me. I did do a compression test and got 135 top cylinder and 140 bottom cylinder. The linkage going under the flywheel to advance the trigger is moving freely. The throttle plate does go perfectly horizontal (wide open) when the tower moves all the way forward. I did notice the the idle adjustment mixture screw ( right above choke plate on front of carb). Seems to doesn't sem to have any affect now. Even it I carefully screw it all the way in til it gently seats, it has no affect when in forward gear with wot. I'm starting to think that a jet in the carb might be clogged. What are your thoughts? Thank you for your help. Ryan in CT

The air/fuel screw on the carb has nothing to do with high speed.
That' controls the low speed air/fuel mix.
Set it at 1 and 1/2 turn out for initial setting.
Than after it's warm you adjust.
There are 2 jets, one in the carb the other on the outside stbd. side.
The jet inside controls the high speed function it could be clogged, or the nozzle(it has small holes) they could be blocked.

Also check the fuel intake.
The connectors,hose, squeezie might be sucking air???
The old inline connectors were famous for going bad.
The squeezie are usually crap and can go bad in 1 second.
I've seen them bad right from the box???

Jerry,
Thank you for getting back to me. My apologies for the delay on replying, been busy at work. I'm convinced it's the carb that needs a cleaning. I'll have it at my house this weekend and I'll check everything you have suggested. I myself have an 1987 85hp force that I love. I too found the force quick connect tank fittings as a big problem and just replaced them with a barbed fitting. This 50hp from 1986 has been a pain in regards to little issues and getting parts. It needs coils soon since the ones on it show cracking but they are so expensive new and hard to find used. Any thoughts on where to get reasonably priced ones? Thanks, Ryan

Just cover them with nail polish or silicone.
Use em till they don't work.
Then try e-bay.
Or Google Marine Salvage yards.