'77 850 dropping rpm

[SkaterRace]

I was out today running WOT and the rpm dropped by about 1000 so I came off plane down to idle and waited a minute then tried again but only got up to about 4k rpm again then I figure I should go back to the dock on the way back (was running about 3000-3200 rpm) it dropped again down to 2500 so I pushed it a bit more to bring it back up to 3000 rpm due to fighting a head wind then. Coming back into the dock I tried to idle slow it down and when I came under 1000 rpm it stalled out. I am not sure what it could be, I will spend the weekend on it if not I am taking it in to have it fixed.

So I did a bit of reading and am now guessing I either have a carb issue or a fuel one. Gas is about 6 weeks old and I put seafoam into it for the first time before this trip. Also could it be because the motor overheated last time I went out which was due to a clogged intake ( I created a thread on finding a filter to solve this issue ). If it is because of the overheating what would likely solve it?

 

[Chris1956]

Well, start with the basics. Do a compression test and a spark test. Inspect the spark plugs for condition. A real clean spark plug can indicate water infiltration. A real dirty one can indicate a no spark condition. Post back with results.

Remember you have two carbs. A clogged carb should affect 1/2 your motor. You would probably not get 4000 RPM or even 3000 RPM with 1/2 the motor not running.