Pre-mix ratio question

rossman21

Seaman Apprentice
Joined
Jun 15, 2015
Messages
34
If i take a sample of gas that has some oil mixed in - is there any way to tell the gas to oil ratio?

I just purchased a sport jet 175 xr 2 that has the automatic oil injection. The original owner said he never trusted this setup so he added a "a quart or so" of oil into the gas tank "just in case" - his thought was better some oil than no oil if the oil injection unit stopped working.

I am going to remove the oil injection system and run it on 50:1 premix. Just waiting on the plastic delete plug that will replace the oil pump.

I have about a half of tank of gas (approximately 12.5 gallons if the gas gauge is accurate). I would like to make the gas in the tank a 50:1 ratio, but I know there is already some oil mixed in - I just don't know how much.

What would you do - would you just put a 50:1 percent into the tank knowing that it will be too much oil (and smoke like a mofo).
Or would you put less oil in (measure out the 50:1 ratio for 12.5 gallons - but not use it all)?
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,469
If i take a sample of gas that has some oil mixed in - is there any way to tell the gas to oil ratio?

I just purchased a sport jet 175 xr 2 that has the automatic oil injection. The original owner said he never trusted this setup so he added a "a quart or so" of oil into the gas tank "just in case" - his thought was better some oil than no oil if the oil injection unit stopped working.

I am going to remove the oil injection system and run it on 50:1 premix. Just waiting on the plastic delete plug that will replace the oil pump.

I have about a half of tank of gas (approximately 12.5 gallons if the gas gauge is accurate). I would like to make the gas in the tank a 50:1 ratio, but I know there is already some oil mixed in - I just don't know how much.

What would you do - would you just put a 50:1 percent into the tank knowing that it will be too much oil (and smoke like a mofo).
Or would you put less oil in (measure out the 50:1 ratio for 12.5 gallons - but not use it all)?
Nope,..... No way,......
Just top it off with properly mixed gas, 'n go,.....

At worst, if to much oil, it might foul the spark plugs abit,.....
 

Dubed

Petty Officer 1st Class
Joined
Sep 3, 2021
Messages
291
Nope,..... No way,......
Just top it off with properly mixed gas, 'n go,.....

At worst, if to much oil, it might foul the spark plugs abit,.....
Bondo, he seems to want to eliminate the oil injection. So, worse case would be too lean and could present issues. PO just added a bit of oil to the tank to keep it a bit rich. Either burn it off with the oil injection and start fresh or drain it and use in your lawnmower,. Start with a fresh tank of 50:1. Just my 2 cents and how I understood it.
 

Bondo

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Staff member
Joined
Apr 17, 2002
Messages
70,469
Bondo, he seems to want to eliminate the oil injection. So, worse case would be too lean and could present issues. PO just added a bit of oil to the tank to keep it a bit rich. Either burn it off with the oil injection and start fresh or drain it and use in your lawnmower,. Start with a fresh tank of 50:1. Just my 2 cents and how I understood it.
Ayuh,..... You maybe right, but that's not how I read this,....
What would you do - would you just put a 50:1 percent into the tank knowing that it will be too much oil (and smoke like a mofo).
Or would you put less oil in (measure out the 50:1 ratio for 12.5 gallons - but not use it all)?
 

Dubed

Petty Officer 1st Class
Joined
Sep 3, 2021
Messages
291
Ayuh,..... You maybe right, but that's not how I read this,....
Yep, sounds like a guessing game but why guess ;).
I raced dirt bikes back in the 80s and we would run those bikes so lean it was rediculous. They were super crisp and had tons of power and response (right up until they didnt LOL)
 

rossman21

Seaman Apprentice
Joined
Jun 15, 2015
Messages
34
Thank you for your suggestions. I am going to take the oil injection out completely (alarm beeps four times and I don't think it's because it is overheating).

I don't know how much oil is already in the gas tank - but I know there is already some.

It is a guessing game - I am gonna measure out 50:1, but not use it all (save only a little in the mix bottle). I figure too much oil is safer than sorry - if I foul the plugs I just clean them and add more gas only to the tank.

I would love to just get rid of the existing gas, but that is 12.5 gallons and I can't store that much (and I won't dump it down the sewer). Got to use what's in the tank first and then I can start fresh!
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
15,417
I would love to just get rid of the existing gas, but that is 12.5 gallons and I can't store that much (and I won't dump it down the sewer). Got to use what's in the tank first and then I can start fresh!
Put it in your truck or car. Will not know the difference
 

harringtondav

Commander
Joined
May 26, 2018
Messages
2,438
Put it in your truck or car. Will not know the difference
I was queuing up the same reply.
Run a vehicle's tank low. Bring the premix to the gas station and dump it into the tank. Top off from the pump. No one will notice except the old 2 stroke motorcycle owners, and they'll just get nostalgic.
 
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