premix = more smoke?

[paulc229]

hello all, i have a 2000 speedster 240 efi gen 1. the boat has a factory rebuilt engine as the original engine was smoked due to the oil pump failing. the previous owner bypassed the oil pump and went with premix. question is, will it smoke more with premix rather than the oil pump? i know that smoke on start up is normal, i wish i had taken a video before i pulled it out of the water. smokes alot at start up, and amytime i run at idle for more than 2 minutes it starts again. how hard is it to revert back to oil pump, and is it worth it in your opinion? also will it smoke more if i have the ratio wrong with too much oil?

 

[Dr Honda]

Generally.... YES, it will smoke more. The reason is... the oil injection system is variable. At idle, you don't need as much oil, as when you are on the throttle. SO... on the gen1 240... idle mix is around 100:1 as I recall. Full power is closer to 50:1. SO... if you premix... then you will be burning 50:1 at idle. In turn, making smoke.


Honestly... if the new engine was installed... I would have just used the oil injection. The newer gear is stronger, and we have figured out that the real issue was the bushings, and engines running hot. Yes... it sucks when the oil injection gear fails... but in all the Merc engines I've seen fail, only a small percent was from gear failure.

 

[paulc229]

Thanks Dr honda, I guess the guy that had it before me thought that since he lost and engine, he should bypass. How difficult is it to revert back to oil pump, I wouldn’t be doing it, my mechanic would, is it going to run up a big bill? In other words is it a big job?

 

[Dr Honda]

It depends...... Are all the parts there? Even if they are there... was the pump running dry? If it was, it will need replacing.

I wouldn't let a mechanic work on you boat. Most of the time, they don't really care, and charge you a fortune. Do the work yourself, and save BIG $$$$$$ !!!!