Gas/oil ratio??? - Snowmobile Forum: Your #1 Snowmobile Forum

BRPforlife · 05-21-2006, 06:02 PM

Hey guys, between work and the cottage I havn't really been on lately. So here's my latest problem. I went for a little boat ride and the old merc was running like poo. I didn't know what gas/oil ratio to put in it so I mixed up some 50:1 hopeing I would strike gold. I don't know much about boats but the motor was smoking quiet a bit more than usual. I'm assuming it's to rich but I don't want to lean out the mix and blow the motor. It's an old mercury 40 from I'm guessing the 80's. Is there any chance that it would run 100:1? Would the exhaust smoke like that if the gas/oil ratio was too lean? What do smaller outboards usually run at? Any help would be great here. Thanks guys

ITriumph · 05-21-2006, 06:38 PM

i got an old '55 Johnson 10hp, and I run it @ 50:1. I'll see if I can find some info for you. Could also be that your running to cold of a plug in it.

ITriumph · 05-21-2006, 06:50 PM

I just did a quick search, and found this in a forum. It looks like your motor should run 50:1. 1 pint to 6 gallons of gas. If it's smokin a little more than the norm, run the next hotter plug, but it won't hurt it if it smokes more than the norm

BRPforlife · 05-21-2006, 07:06 PM

Thanks mouse. I'll keep it at 50:1 and clean the carbs to see if it makes any difference.

SnowRida · 05-21-2006, 08:42 PM

50:1 should be fine. Make sure you have the right plug. A little smoke is better than than none. You don't want to run lean.

BRPforlife · 05-21-2006, 08:57 PM

Quote:

Originally Posted by SnowRida

You don't want to run lean.

Exactly my thoughts. It would stall at idle and run rough at higher rpm's and have trouble running for more than 5 or 10 minutes. Compression was great on both cylinders so I'll tear out the carb and see if it's gunked up. It probably hasn't been cleaned since the 80's so I'm betting that's the problem now that I'm sure it's not running rich on oil!

Thanks guys

G-ForceJunkie · 05-21-2006, 09:27 PM

Go to a dealer and find out the proper ratio, it would suck running 50:1 on a motor that only needed 70:1

letitsnow · 05-21-2006, 11:08 PM

i was surprised when i found my yamaha 30hp used 100:1, i never knew these things ran so lean.

**smallengineguy** · 05-22-2006, 07:07 AM

Buy the "Exact mix" synthetic oil in the little bottles. It doesn't matter what the ratio it is; you use one bottle to one gallon. Never fails. ALso don't go up more than one size on the plug. It'll just hot spot that section of the piston and could cause problems later on.

Formula_Canuk · 05-22-2006, 07:19 PM

I've run 50:1 in every 2 stroke outboard I've ever owned. Your problem could be water in the gas, or something as simple as some trash in the needle and seat assembly. Not much to go wrong on these things. You can buy a carb rebuild kit at any decent marina for like $30.

G-ForceJunkie · 05-23-2006, 05:08 PM

Quote:

Originally Posted by smallengineguy

Buy the "Exact mix" synthetic oil in the little bottles. It doesn't matter what the ratio it is; you use one bottle to one gallon. Never fails.

Say what?

Formula_Canuk · 05-23-2006, 05:58 PM

Yea, I'm confused too

(Although that isn't that hard to do

)

OILBUG · 05-25-2006, 09:57 PM

Amsoils Sabre Outboard Designed for applications as lean as 100:1 ratios.
This improves throttle response, lower or eliminate smoke, minimize deposits and lowers emissions. for more info go to lubedealer.com/go
Not sure which ratio you need but I used this oil and it worked fantastic for me.

**smallengineguy** · 05-26-2006, 06:48 AM

C'mon..You've never heard of exact mix? It's brilliant! You use the same mix whether it's 20:1 or 100:1. Check it out at hardware stores, etc.

BRPforlife · 05-30-2006, 02:09 PM

Hey guys,
I hate seasonal work. Sure you get winters off but during the summer you have absolutely no life! Anyways, I tore out the carb and cleaned it. I phoned a merc dealer and he said to run 50:1. Got it back together and running and adjusted the air/fuel mix a bit. It runs great! Like it was 1980 again. Thanks for all the help guys.
I'll keep my eye out for that stuff next time I'm in canadian tire SEG. Almost sounds too good to be true!

Formula_Canuk · 05-30-2006, 04:00 PM

Good to hear. I have never seen this exact mix stuff? How does it even work?

PolarisINDY500 · 05-30-2006, 04:14 PM

Quote:

Originally Posted by OILBUG

Amsoils Sabre Outboard Designed for applications as lean as 100:1 ratios.
This improves throttle response, lower or eliminate smoke, minimize deposits and lowers emissions. for more info go to lubedealer.com/go
Not sure which ratio you need but I used this oil and it worked fantastic for me.

welcome to the forums OILBUG

**smallengineguy** · 05-30-2006, 09:00 PM

It's fully synthetic 2 stroke mix. I Googled it, but nothing came up worth a crap.