1993 25 HP excessive smoke

[Springbok142]

I just bought a Princecraft Pro Series 142 with a 1993 25 hp Johnson (VJ25ELETC).

I had it out on the water for the first time and it seems to smoke excessively. I thought maybe the previous owner had too rich of an oil to fuel mix and made up a fresh tank of 50:1 mixed gas but with no change in the amount of smoke. The engine smokes right on startup (which takes multiple cranks to get going when cold) but seems to smoke more after a run at full throttle when going back to an idle. The smoke is white in colour.

I pulled the plugs out and they have an oily black residue on them. The spark plugs in the motor were NGK BR9HS and the Clymer manual I have recommends Champion QL77JC4. Is the NGK compatible or is it causing or compounding my problems?

I will be replacing the impeller this weekend as it takes about 8 seconds after firing up before water comes out the telltale and when it does it is not a forceful stream. How long should it take to see water out the telltale with a new impeller? I also had what was most likely a high temp alarm when out on the maiden voyage and shut the engine down right away to let it cool down.

Any help or suggestions would be greatly appreciated as I don`t have much experience with outboards.

Thanks,

SB142

 

[tx1961whaler]

Re: 1993 25 HP excessive smoke

The impeller needs replacing.
The motor should run Champions. There is the risk of burning the pistons up if the NGK's are too hot of a heat range.
Try doing a decarb procedure to reduce the smoking. Instructions here: http://forums.iboats.com/showthread.php?t=302825

Using full synthetic 2-cycle oil helps with the smoking

 

[kenmyfam]

Re: 1993 25 HP excessive smoke

Change impeller, check the rest of the water pump while in there. Use the recommended champion plugs and decarb the motor.