pre-mix ratio?

[bassassin85]

I have recently acquired a 1985 9.9hp Johnson. I will be using it as a kicker motor on my 18ft sea nymph. My question is that on the motor is states to run the fuel 100:1. This seams awfully lean to me as I have always ran 50:1. Will this motor run OK on such a lean mix with out burning it up? And will it hurt it to run it on 50:1 as that's what I run in my primary motor.

 

[Bifflefan]

Re: pre-mix ratio?

I do belive that 100:1 is the correct ratio, Now it will run on 50:1 fine. Maybe foul a plug now and then, maybe not.
I run everything (except the boat motor) on 32:1 and ive never had any issues with this. Thats a chain saw, snow blower, leaf blower, they are all 50:1 and my back pack blower is 32:1. Just dont like to mix 3 types of gas.
Also hte guy at the small engine shop says told me it was fine.

 

[bassassin85]

Re: pre-mix ratio?

I do belive that 100:1 is the correct ratio, Now it will run on 50:1 fine. Maybe foul a plug now and then, maybe not.
I run everything (except the boat motor) on 32:1 and ive never had any issues with this. Thats a chain saw, snow blower, leaf blower, they are all 50:1 and my back pack blower is 32:1. Just dont like to mix 3 types of gas.
Also hte guy at the small engine shop says told me it was fine.

Well that's my concern is fouling plugs as it will mainly be ran at low rpm's for trolling. I'm the same way about mixing fuel, everything of mine run's on 50:1. Never had an issue but 100:1 just seems awfully lean.

 

[Capt Ron]

Re: pre-mix ratio?

Run it on 50:1 it will be just fine.
I haven't checked but the change to 100:1 may be an environmental issue...wouldn't surprize me none.
Besides, it's better to have a fouled plug than a fried piston.
Remember the old days of adding the required oil if you weren't sure a tank had any?

Capt Ron

 

[tx1961whaler]

Re: pre-mix ratio?

When that motor came out in 1985, Johnson specified a 100:1 ratio. However within a couple of years they recommended that the motor be run at 50:1, due to issues with internal rusting on motors that were stored for longer periods of time. If the motor were ever at a dealer for service, they would have removed the 100:1 label and put a 50:1 label on it.

Oil recommendations from Evinrude can be found here:
http://www.evinrude.com/en-US/About.Us/FAQ/Oil.Fuel.htm?popup=true

 

[bassassin85]

Re: pre-mix ratio?

Thanks for the help.