1987 90hp johnson fuel question

[dsujen]

I just bought a j90tlcur motor. It was off the guys boat and he wasn't able to prove it runs. I bought it as is. I put it on my stand and did a compression check. It was good. It has a remote oil tank and vro pump. I hear that the oil tank set up is no good and I should mix my own gas. Is this true? Before I spend any more on the motor that I haven't seen run I'd like to run it. Any tips on what to do as far as making sure the oil is getting to the motor. I never had an oil injection set up and I don't want to blow it up on the initial test. Should I change it over and mix my own gas and if so how?

 

[Will Bark]

Re: 1987 90hp johnson fuel question

For your testing I would go ahead and mix your fuel at 50:1 and leave the VRO hooked up; put a mark on the tank to check and see if the oil is moving out of the tank. That way if its not you won't burn your motor up.

 

[dsujen]

Re: 1987 90hp johnson fuel question

won't mixing the gas and letting it run with the oil tank hooked up make it twice as much oil in the gas?

 

[Fed]

Re: 1987 90hp johnson fuel question

Double oil won't hurt it at all.

 

[dsujen]

Re: 1987 90hp johnson fuel question

How long on the muffs should it take to see oil missing in the tank?

 

[Fed]

Re: 1987 90hp johnson fuel question

Too long. LOL!

 

[emdsapmgr]

Re: 1987 90hp johnson fuel question

Good suggestions. The engine will smoke more, but the test will validate whether the VRO is properly working. You really need to test the engine under normal water test conditions in order to run enough fuel/oil through it to see the oil tank go down.

 

[racerone]

Re: 1987 90hp johnson fuel question

Manuals have a test procedure.-------Run on 50:1 from fuel tank.----Remove oil line from VRO,-----------Install a loop of clear hose to the VRO.----Fill that loop with oil.------Start motor and see if VRO pulls the oil level down in that loop.

 

[Fed]

Re: 1987 90hp johnson fuel question

The oil level in the bottle should drop about 3/4" for every 10 gallons of fuel used.

 

[dsujen]

Re: 1987 90hp johnson fuel question

I just want to make sure the motor runs before I put any money into it. How about pre mixing the gas and oil and gravity feeding the carbs directly? If I hang the fuel tank higher than the motor will this work?

 

[avantifishski]

Re: 1987 90hp johnson fuel question

just unhook that POS vro I just walked in from doing it to my 1988 90hp Johnson..it still smokes some at 50:1 but runs pretty dam good..1700 RPM at idle hope to do open throttle test in the lake 2morrow..

 

[dsujen]

Re: 1987 90hp johnson fuel question

how did you unhook it? If you could, explain it to me as far as what you disconnected and what was plugged or modified.