general question about gas/oil ratio

[CKJR]

several months ago i was speaking to a teck who had indicated that a outboard can safely run at a oil gas ratio of 150:1. the added oil is only required when the motor sits idle for several weeks (cylinder rust). has anyone else heard this. i feel that that ratio is very lean. the motors i am referring to are johnyrudes.

 

[mgerle]

Re: general question about gas/oil ratio

yea, I did that with an old rebuilt 175 merc that we dragged out of the boathouse. It sat for 3 yrs, yet the plugs showed full of oil residue. Ran it for a minute lean, just to clean it up. Dont take the advice from me, I just made up the theory myself.

 

[JB]

Re: general question about gas/oil ratio

Nonsense, CK.<br /><br />I am amazed at some of the crap so-called technicians might say to a customer.

 

[DJ]

Re: general question about gas/oil ratio

Ditto JB,<br /><br />If it were true, the manufactures would have promoted that information long ago.

 

[jroberts24]

Re: general question about gas/oil ratio

I am not a outboard mechanic by far, but what I do know is that too much oil is better than not enough. The only thing that can happen with too much is a lotta smoke, fouled plugs, or carb gum. That is a lot better than a locked up engine. 150:1 is way too lean. Your engine may over heat if you run it too much with that mixture.<br /><br />jroberts

 

[Boatist]

Re: general question about gas/oil ratio

CKRJ<br />Run it at 50 to 1 if it is a newer motor. Older motor were 24 to 1.<br /><br />I will tell you a OMC Factory rep told me I could run my 1975 15 Hp at 100 to 1 with out damage if I only ran at trolling speed. At mid to high speed must have 50 to 1. This was in responce to a plug fouling problem I was having at the time. Never tried it. Problem turned out to be thermostat stuck open and Carb Float not shuting off the fuel.

 

[CKJR]

Re: general question about gas/oil ratio

i also believe that more oil is better than less. i was a little curious on the exact minimum amount of oil a motor can run safely, this is not an experiment and i do not plan to do any testing. the factory rep did indicate to me that new motors are run at the factory at 150:1 all day with no ill effects.

 

[roscoe]

Re: general question about gas/oil ratio

Johnson (and others?) tried a "recommended 100:1" back in the 80's. It didn't work and motors were failing. My dealer called and told me to use 50:1 per Johnsons new instructions. They said it was an overheating and metal protection issue.<br /><br />Use the 50:1.