Premix gas in line to 4 stroke kicker

sly_karma

Crew Member
I took my boat to local marine mechanic for work on timing and tuning that are above my pay grade and no time to learn at the moment. The engine is a 2 stroke Merc 150 with oil injection disabled. I had a 6 gallon tank of premix hooked up via my fuel system with filter when i dropped it off, and I deliberately removed the 3 gallon tank of straight gas that runs directly to the 4 stroke kicker. Picked up the boat today and I noticed they had somehow used the kicker fuel line to connect the premix tank to the main. Phew! Thank god I took away the unmixed tank! [Note to self - change gas tank fittings on this straight gas tank so it can't ever be inadvertently connected to the main].

Anyway now I have about 7 ft of 3/8" gas line all primed up with 50:1 mix and it runs to my 4 stroke kicker. Do I flush it out or will the Merc 9.9 just run smoky for a bit and not really care? That line would contain maybe 1/2 cup of gas.
 
I'm gonna suggest that you are gonna be ok any which way you deal with this. If you can disconnect the line and flush that little bit then why not do it. If it's too cumbersome start the kicker up, rev a bit higher than normal and run it for a bit.
 
You will have no issues at all. I often run my 4 strokes on mixed gas it does absolutely no harm to the engine. You could run it for days on mixed gas with no harm. The combustion chamber on a 2 stroke and 4 stroke are made of the same components , a spark plug is a spark plug what harm can be done.
 
It might smoke a bit but will be fine. You could also flush whatever you can of the pre-mix in the kicker line back into your pre-mix tank if you want a little extra peace of mind.
 
I run my 4-stroke lawn mower on the same mixed fuel as my other 2 stroke tools, and no problem at all.
doesn't even smoke
 
Would it make oil over time? Turn the oil a blue-ish color?
 
I bought an used older honda 8hp 4 stroke that came with a small tank that had some mixed gas in it that I didn't know about, never even thought there might have been mixed gas in it. I had seen the motor run a few days earlier and thought nothing of it. Got the motor home, mounted it on my boat and tried to start it with the aux. tank that was half full that came with the motor, it wouldn't run. I'm thinking to myself what the @#$*&^%$. Pulled a plug and had a look, and it smelled of oil, looked in the tank and poured a little out and it was mixed. Dumped the tank, put some 94 oct. CHEVRON in it and purged the fuel line, cleaned the plugs, started on first pull. Long story, short, purge the fuel line, it's not worth the hassle.
 
I bought an used older honda 8hp 4 stroke that came with a small tank that had some mixed gas in it that I didn't know about, never even thought there might have been mixed gas in it. I had seen the motor run a few days earlier and thought nothing of it. Got the motor home, mounted it on my boat and tried to start it with the aux. tank that was half full that came with the motor, it wouldn't run. I'm thinking to myself what the @#$*&^%$. Pulled a plug and had a look, and it smelled of oil, looked in the tank and poured a little out and it was mixed. Dumped the tank, put some 94 oct. CHEVRON in it and purged the fuel line, cleaned the plugs, started on first pull. Long story, short, purge the fuel line, it's not worth the hassle.
It was more than likely old stale gas possibly water in it, trust me it wasn't the oil.
 
It was more than likely old stale gas possibly water in it, trust me it wasn't the oil.
It wasn't old gas or water in it, you can smell old gas. Where I bought the motor from wasn't a private deal and where I bought it from went through plenty of gas. So I don't think it was old or H2O in it, but there was oil in it. I didn't mention it before but I flushed it from the tank to the fuel pump, (ya through the carb too) and it ran. Sly Karma that little bit of gas isn't worth the hassle.
 
It wasn't old gas or water in it, you can smell old gas. Where I bought the motor from wasn't a private deal and where I bought it from went through plenty of gas. So I don't think it was old or H2O in it, but there was oil in it. I didn't mention it before but I flushed it from the tank to the fuel pump, (ya through the carb too) and it ran. Sly Karma that little bit of gas isn't worth the hassle.
There must have been different issues maybe way to much oil like not a proper ratio 40-1 50-1 etc because you can run any motor with the proper oil/gas mixture without a problem. Done it millions of times without a single issue
 
Back
Top