'94 90HP Yamaha Oil Injection Bypass

[waterbill]

My 18 year old engine still runs great. But I wonder if the oil injection sysyem may one day quit working. Since it is so old, would it be advisable to bypass it and pre-mix the fuel in the gas tank? Also,does 2-cycle mixed with ethanol gas go bad sooner in a tank than just straight ethgas? How do I disconnect the system, if in fact it is advisable to do so? And lastly, what is the ratio to use? If anyone out there has done this or would give some advice, I will appreciate it greatly. Thanks.

 

[99yam40]

Re: '94 90HP Yamaha Oil Injection Bypass

gear driven pumps do not go bad normally, it is the non maintenance of oil system that plugs lines and check valves up with sludge.
clean things up and test system like Yamaha calls for and leave it on

 

[Bamaman1]

Re: '94 90HP Yamaha Oil Injection Bypass

Yamaha oil systems are mechanical. The electric module is just to move oil from the big external oil tank to the little internal oil tank under the engine cowling. They're really trouble free systems.

I would suggest just watching for a puff of blue smoke exhaust when you first start the engine and watch to see that the oil tank level goes down.

I always watch to make sure my Yammie is "peeing." I've only changed one thermostat and one water pump impeller in 26 years of use. I think I'll borrow a pontoon trailer, pull my boat, clean it and check the engine out next week.

They're really pretty trouble free and reliable engines.

 

[99yam40]

Re: '94 90HP Yamaha Oil Injection Bypass

Bam,
problem with letting things go that long is some of the bolts may not come out after that many years