1969 Merc 1000-Can Carbon plug Exhaust?

[NJCinMN]

OK..done/checked
125 psi across all cylinders
spark on all 6 verified
new fuel lines and bulb
rebuilt fuel pumps with new check valves
rebuilt carbs-full kit, new everything needles seats etc.
new plugs
lync & sync, timing...on the nuts and 3 carbs fully opened

Just me in 1969 glastron v-163, jumps out of hole and runs right up to rpm but
turning only 4500 rpm @ WOT & 35 mph
aluminum 17 pitch

Can carbon build-up plug exhaust and cause loss of power/rpm? or am i overpropped? exhaust doesn't seem real loud when on muffs. any thoughts or advice, ideas, anything cuz i'm out of them other than going to a 15" prop.

 

[BR]

Re: 1969 Merc 1000-Can Carbon plug Exhaust?

NJ-
Have you verified that WOT at remote control opens carb butterflies fully? Could be a throttle stop adjustment. I believe the exhaust can become restricted by carbon, however if you're otherwise running alright I would doubt that carbon is your problem. Try a decarb fuel treatment and see if it helps - can't hurt!

Good luck!

 

[NJCinMN]

Re: 1969 Merc 1000-Can Carbon plug Exhaust?

BR
Butterflies are wide open just shy of each of their individual stops when dissy/economizer assembly hits max throttle stop. Yeah it runs great, fires right up, idles, goes into gear without a miss, jumps out the hole and runs up....just seems to run out of rpm's???? But like I said exhaust seems awful quiet when out of water compaired to other outboards.

 

[Fuzzytbay]

Re: 1969 Merc 1000-Can Carbon plug Exhaust?

Try the 'seafoam" treatment, one can seafoam, to a gallon of fuel, just make sure its outdoors, it gets pretty smokey. On the whole though, I guess its a prop problem, heres a link to a prop/pitch site for the oldies. http://www.maxrules.com/propindex.html