Fuel Oil Ratio?

[supercoolbabe]

I think that I have goofed up. I have a 52-54 Johnson 3hp JW-10 that I had been running 50:1 fuel ratio. I just acquired the manual and it says to add 1/2 pint oil to the fuel which I believe makes it a 25:1 fuel ratio. (I didn't know any 2 stroke motor ever ran on anything but 50:1 because I am younger than the motor.) It ran fine for several months. Then I started having trouble keeping it running. I have rebuilt and cleaned the carborator(except the float, it is not cork though) but it starts hard and doesn't run for more than a couple of seconds-minutes. It runs the longest when I close the fuel tank for some reason. Any suggestions would help. I really like this motor.

 

[F_R]

Re: Fuel Oil Ratio?

Actually, 1/2 pint per gallon is 16:1. Now that you have demonstrated how tough that little motor is, give it a break and use at least 24:1

I suggest you check the fuel filter in the tank. Some of them were made of sintered metal and when clogged are impossible to get gas through --or even clean them.

The other thing to check is the ignition coils. If they haven't been replaced yet, they need to be. The originals are guaranteed to be cracked and NG.

 

[supercoolbabe]

Re: Fuel Oil Ratio?

Ok. I feel bad about the lack of knowledge. Wow, so should I use the 1/2 pint or does the ethanol fuel of today need more oil. I want to do what is best.

The fuel filter is a very fine screen, It almost looks like a "porous rock" rather than a screen. I have sprayed cleaner through the valve assembly and it comes out of the screen clean as far as I can tell.

Thanks for the ignition coil tip. I'll check on that.

 

[supercoolbabe]

Re: Fuel Oil Ratio?

Coils were replaced by the mechanic I bought motor from.

 

[JB]

Re: Fuel Oil Ratio?

If it runs better with the tank vent closed you have an over-rich condition, Babe. Could be the float, float setting or simply adjustment of the carb jets.

In the Engine FAQs there is an article by Joe Reeves on initial setting and fine tuning of the mixture controls. Check that out..

Good luck.

 

[supercoolbabe]

Re: Fuel Oil Ratio?

If it runs better with the tank vent closed you have an over-rich condition, Babe. Could be the float, float setting or simply adjustment of the carb jets.

In the Engine FAQs there is an article by Joe Reeves on initial setting and fine tuning of the mixture controls. Check that out..

Good luck.

Thank you again. I really appreciate your help. You are very kind to share correct knowledge with us. I am so glad I found this site.


"The more I learn, the more I understand how little I know"

 

[F_R]

Re: Fuel Oil Ratio?

With great respect for JB and his knowledge, his logic about the closed vent and rich/lean conditon is very valid as far as it goes. But let me say that if it runs better with the vent closed it is possible that it runs better because heat is building up in the tank from running and/or the sun and that is pressurizing the tank and forcing more gas through that "stone" filter.

Take the gas line off the filter and see if you get a good flow from the tank with the vent open. Do this with a partial tank of gas because the filter could be only clogged on the lower portion and fine on the upper portion. Did I mention that they are somewhat troublesome?

 

[JB]

Re: Fuel Oil Ratio?

Good point, F_R.

 

[supercoolbabe]

Re: Fuel Oil Ratio?

Would it br better to remove it and put a screen filter on the valve? Or is there a newer replacement part? My two has a very fine screen filter that functions well.

 

[tx1961whaler]

Re: Fuel Oil Ratio?

I don't think there is a replacement part for the filter assembly. The original metal "stone" one is soldered in, and can be removed with a blowtorch (away from the gasoline, of course). The replacement screen can be soldered in it's place over the hole. Or you can get ambitious and splice in a teeny in-line filter in the short fuel line, but then you're adding 4 tiny hose clamps and some flexible fuel line into the equation. More stuff to break later!

 

[killmeister]

Re: Fuel Oil Ratio?

Actually, 1/2 pint per gallon is 16:1. Now that you have demonstrated how tough that little motor is, give it a break and use at least 24:1

I suggest you check the fuel filter in the tank. Some of them were made of sintered metal and when clogged are impossible to get gas through --or even clean them.

The other thing to check is the ignition coils. If they haven't been replaced yet, they need to be. The originals are guaranteed to be cracked and NG.

Hello:
I have recently inherited a 1960 Johnson Sea Horse, 3 hp outboard, Model JW-16 that came with no manual of any sort. I have been told to use a 24:1 gas to oil ratio. I have recently read that 87 0ctane gasoline is not good for outboard motors and to use a mid-grade gasoline as the highest octane is also bad for the engine. Can anyone verify if this is true or not? Also, presumably the "oil" to use is TCW-3? Please verify this for me. Thanks.

 

[tx1961whaler]

Re: Fuel Oil Ratio?

24:1 TCW-3 oil and 87 Octane gas will work just fine.
I also use Sta-Bil and Sea Foam additives, since I switch the small kickers around often and don't know how long they'll set around...