I have a 1987 yamaha 50hp on my 20' pontoon. It has a couple of problems.
I always thought it was running near max rpm because of the sound of the engine but I recently bought a cheap lcd tach on ebay and I saw a max of 5250 rpm at about 18mph gps with 3 people and coolers and tubes and stuff for the day.
I can't see all the numbers on the prop but it looks like it says 11 1/4 x 13U but I am only positive on the 13U part.
What prop would be good for me?
Also it seems to run great above 2,000rpm but between idle and 2k it runs rough. it doesn't ever actually die but it seems like it could. Idle goes down to 750-850 in gear.
The rough running smooths out completely after 2k. I just went through the carbs and the plugs look pretty good.
Any ideas on the rough idle?
I always thought it was running near max rpm because of the sound of the engine but I recently bought a cheap lcd tach on ebay and I saw a max of 5250 rpm at about 18mph gps with 3 people and coolers and tubes and stuff for the day.
I can't see all the numbers on the prop but it looks like it says 11 1/4 x 13U but I am only positive on the 13U part.
What prop would be good for me?
Also it seems to run great above 2,000rpm but between idle and 2k it runs rough. it doesn't ever actually die but it seems like it could. Idle goes down to 750-850 in gear.
The rough running smooths out completely after 2k. I just went through the carbs and the plugs look pretty good.
Any ideas on the rough idle?