115 timing

[bobt]

I've recently purchased a boat with a 94 yamaha 115 hp precision blend. The plugs seem to get oily and foul after three or four trips causing the motor to stall at idle. Runs fine otherwise. The manual I have (Clymers) says the timing should be set at 25 degrees BTDC using a dial indicator. Can this be done using a timing light with the motor running? If the timing is good can I run a hotter plug? Thanks for any information. bobt

[boats.net]

Probably need to do a compression test and check condition of fuel pumps and carbs.
Timing needs to set with a timing light.

[99yam40]

The dial indicator is to make sure the pointer is in correct position and then use the timing light

[bobt]

115 timing

Thanks for the replies. I've redone the carbs and will check the timing. Compression is good. I will probably replace the fuel pump as I've read this is good preventative maintenence for every three or four years on these motors. Could this be limiting the fuel causing the fuel/oil mixture to be off, thus the oily plugs? How about plugs one heat range hotter. Is this a bad idea if everything else checks out? Thanks, bobt

[99yam40]

I would not run plugs that were not in the spec's for the motor