I've got a 16 hp go devil long tail (58" shaft) Vanguard engine that doesn't seem to be giving enough RPM's with a load under it.

Without a load it gives about 4000-4150 RPM's (which is about were its supposed to be without a load)

With a load, when I run it in the water it only gives me about 3000-3200 RPM's (it should be giving a minimum of 3400 RPM's with a load)

The motor doesn't sound like its at wide open with the throttle at max, I feel like it should be giving me more.

Initially I thought the prop was worn and putting to much load on the engine, I put a brand new prop on it. Still, same result of 3000 RPM's.

I bent the governers tab out and readjusted the fuel mixture screw on the carb which gave me roughly about 200 more RPM's putting me at about 3100-3200 RPM's with a load. But still I feel like it needs to be at a minimum of 3400 RPM's in the water.

Ive got it on a small flat bottom, 14x32 duracraft, and always carry light gear so its not the boat putting a heavier load on the engine.

I just had the engine serviced, oil change, carb clean, new air filter and spark plugs about 2 months ago

I attached a video of how its running with a load in the water.

Any suggestions on how to get my RPM's up were they need to be?

Are you sure the carb is opening up all the way. Since carb was serviced the throttle cable could have not been set right and you aren't getting full travel.

Thats a good point, the guys I had service it don't specialize in mud motors so im skeptical that something like that could be the problem. How do I go about looking to see if the carb is opening up all the way or not?

Hah dumb question sorry, Look down in the carb and see if its opening up all the way when I hit the throttle..

you should be able to tell by the stopper flange on the side of the carb the linkage is connected to a pin if you will that is pulled between the idle screw and the tab (your throttle range)

Im following you, does the attached vid answer any questions? This is the stopper flange where the pin is trying to move back and forth as I'm opening and closing the throttle.

I've sprayed it down pretty good with carb cleaner and it still looks dirty/ isnt moving freely, I dont know if that has anything to do with it.

Thanks for the advice

Sounds like to me you need to take the carb completely off. Pull all the Jets out of the carb and clean them good. Don't just take the carb off and spray it with carb cleaner and brush it. The big thing is removing the Jets and cleaning inside them. Always run some sea foam or k100 in the gas. And if you have to go through the trouble of cleaning the carb then u prob should replace the fuel lines and the fuel filter.

Thanks ya i guess thats what il have to do, at first I was ruling a carb issue out because I just had it cleaned and readjusted a couple months ago.