76 25 hp Rude Black Sludge?

[69 Alumacraft]

Bought the motor in the spring, prev owner said carb was rebult, one new coil one newer. Ran well all summer, one trip it just bogged down and cut out. Replaced fuel pump, took off carb, disasembled, had new float gaskets, needles looked good so I soaked it and reassembled, new plugs. Fire right up but after about 3 minutes it started to miss and got worse and worse till it died and would start but sounded like only one cylinder was firing. Checked plugs and top one was black and wet and bottom looked good. Finally lost patience and took off LU to use with a 69 25 hp that I had as a part motor b/c LU was no good. When I took LU off there was carbon charcoal caked on to shifter rod and black sludge in the LU (not inside gear case). Did I blow the head? New points? Engine was smokey but seemed to run strong, no evidence of overheat on block (paint still good ). BTW 69 started right up and seems to have more power than 25. I have the selock manual and patience. ANy advice appreciated! No one has any advice!?

 

[69 Alumacraft]

Re: 76 25 hp Rude Black Sludge?

Anybody out there? In need of a serious de-carb? Seafoam or Yamaha stuff? Bad coil? Why so much sludge/ carbon build up?

 

[69 Alumacraft]

Re: 76 25 hp Rude Black Sludge?

Anyone? Tell me to reread secret files?

 

[bktheking]

Re: 76 25 hp Rude Black Sludge?

Sure, check for spark, one dry one wet is indicitave of no spark. It may seem strong in a barrel, running on 1 cylinder they always do. The tell tale is on the lake, won't plane the boat. Black sludge is unburnt fuel, pull the flywheel and inspect.

 

[grub_ba76]

Re: 76 25 hp Rude Black Sludge?

im not a expert and not a 100% sure but my motor runs fine and all ways has since ive owned it (no missing etc) and i all ways get alot off black sludge up there and have also done carbs to...im thinking its just over time cause its old and from build up (its like a grease) but then again its also saying its not burning fuel probly but running it on grass does not kill grass or leave black spots like my old suzukis used to cause someone put bigger jets in carby causing it to get to much fuel, plus there was a miner spark problem and it used to leave big black spots on my grass and run out of prop for a few days.
being a 2 stroke its normal to get a oily supstance coming out exhuast over a long time isnt it? as my lawn mower and wiper snipper does.
hopfully somone can correct me