Mercury 800 80hp, won't go past 2500 rpms

Hi all i'm new to iboats and boating hoping i could get some help with my boat, So I bought a boat 17' with a 70's Mecury 800 80 hp motor. It is hard to start most the time until it's warmed up, it runs fine on muffs, revs up everything sounds great but when i put it in the water i can only get to about 2500 rpms, last year it would bog after about 2 minutes running at 2500 rpms. This year i've had a friend come and help me with it, we've changed the spark plugs checked out the distributer(it's ok but was pretty corroded we cleaned it up pretty good though) we've also adjusted the screws on the carbs as best we could and it runs now better than when i got it, It doesn't bog anymore but i still can't get more than 2500 rpms. i probably need a distributer but was wanting to find out for sure before i buy one,
Thanks,
Shay

Re: Mercury 800 80hp, won't go past 2500 rpms

ok well first off check compression make sure thats good. then check spark. might as well replace ur water impeller. check gear oil and replace. once u fingure out u have a good motor.

then after might as well go and clean and rebuild ur carb. then see if pumping ur primer bulb will help with the rpms if does then rebuild fuel pump and be safe replace fuel lines and such

Re: Mercury 800 80hp, won't go past 2500 rpms

Most inline 6's are a bit hard to start cold, you need to almost flood them to get em going, once warm they start fine. Now I am guessing at the age of the motor, posting the S# would help. Since your new, and to you so is the boat and motor, you start with the basics, look at the plugs, test the engine compression, clean the carbs, and do a link and sync. The first test is pretty simple, pull the plugs, look for even colouring, a brownish colour's good, with no build up of oil, metal etc. Second once the plugs are out, check the compression, the cylinders should all be within 10#'s of each other, 110-130 would be good, 90-110 should still run.third one might be tricky, if you have never done it, but with the help of this forum, its not all that hard. Here is a link to the fourth item, the link and sync. http://forums.iboats.com/showthread.php?t=168855
I wouldn't start buying parts, untill you narrow done the problem, to me sounds like simple stuff, more like a fuel/air mixture issue, or even incorrect prop pitch.

Re: Mercury 800 80hp, won't go past 2500 rpms

i guess go ahead check ur prop pitch and make sure at the controls the butterflys all of them r wide open