Whats Wrong with my 78 Johnson?

Joined
Sep 29, 2011
Messages
22
Hey boating people, I recently bought a 1984 (its a 1984..sry for the bad title…) Johnson 115 VRO outboard (and boat). The engine has 2 cycle oil injection.

When I was going over the boat it became obvious that the boat had been at least partially filled with water. From all appearances this was rain water (scum ring inside the boat) so I do not think the outboard was submerged. However, the batter(ies) were submerged along with the oil-injection reservoir. The battery cables and switch were corroded and were replaced, along with new batteries. The 2 cycle oil reservoir and lines were drained, cleaned and reconnected.

I have not yet tried to start it with the injection oil. I did try to run the outboard from a new tank of premix gas, which resulted in the engine starting up right away, but dying within a few seconds. I tried the prime/choke button and this allowed the engine to stay running until you stop periodically pushing the button. Then it would quit again. I pulled and cleaned the plugs a few times, they were coated in oil. Then I read up on oil-injected outboards, and I read that running on premix does not lubricate the crankcase, just the cylinders, so I stopped trying the premix.

My question is: Is it just the oil injection system getting filled and primed the solution to this issue, or do I have a separate issue like not enough gas getting into the cylinders? I MAY have sucked water in through the oil injector res that had filled up with water... Would this cause an issue like this?

I looked at some diagrams of oil injected outboards and it looked like oil gets injected AFTER the pure gas, but one thought I had was could water have gotten into the carb bowls?

last question: Is it difficult to remove the oil injection system and just run it on premixed gas?

Any advice or pointers would be greatly appreciated.
 
Last edited:

coolbri70

Lieutenant Commander
Joined
Oct 6, 2011
Messages
1,554
Re: Whats Wrong with my 78 Johnson?

I would not trust the oil injection but that's me, didn't think they had it then. check the fuel pump
 
Last edited:

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,473
Re: Whats Wrong with my 78 Johnson?

??????----Oil injection did not come out on a 1978 model.----First year was 1984 for them.------So the model # needs to be posted to get the right information.------You are sadly mistaken on how lubrication works on this outboard motor.----When gas and oil are mixed then ALL THE PARTS get proper lubrication , including the crankcase and the fine parts inside .------Get a manual first to avoid costly mistakes.
 
Last edited:
Joined
Sep 29, 2011
Messages
22
Re: Whats Wrong with my 78 Johnson?

It is in fact a 1984 model #J115TLCR serial #5962854. Glad to hear I got the wrong info on lubrication. I will get the manual and read up on this outboard. Last owner was full of crap about many things, outboard year being one of them.

One question though, does the prime/choke button push gas into the cylinders with the fuel pump?
 

coolbri70

Lieutenant Commander
Joined
Oct 6, 2011
Messages
1,554
Re: Whats Wrong with my 78 Johnson?

having to prime it to keep it running is a sign the fuel pump isn't working, by keeping it primed you are manually pumping fuel, check the pump
 

coolbri70

Lieutenant Commander
Joined
Oct 6, 2011
Messages
1,554
Re: Whats Wrong with my 78 Johnson?

It is in fact a 1984 model #J115TLCR serial #5962854. Glad to hear I got the wrong info on lubrication. I will get the manual and read up on this outboard. Last owner was full of crap about many things, outboard year being one of them.

One question though, does the prime/choke button push gas into the cylinders with the fuel pump?

that is good as I think the 78 was the last year of electric shift, which I read can be problematic( I was misinformed, 72 was last of electric shift )
 
Last edited:

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,473
Re: Whats Wrong with my 78 Johnson?

1972 was the last year of production of electric shift outboards !!--------If running improves when you push in the key then the fuel pump is working !--The primer gets fuel presssure from the pump.-----If running improves when operating the electric primer you have issues in the carburetors.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: Whats Wrong with my 78 Johnson?

The fuel primer (electric choke) solenoid opens when you push in on the key switch (when the key is on..) The normal fuel pressure of the pump also pressurizes the fuel to this solenoid and it pushes through small rubber choke hoses to the brass hose barbs on the top of both carbs. These small brass tubes distribute (squirt) fuel into both barrels on each carb. That's why racerone added the last comment (#8)
 

coolbri70

Lieutenant Commander
Joined
Oct 6, 2011
Messages
1,554
Re: Whats Wrong with my 78 Johnson?

I thought he was talking about the primer ball:facepalm: my mistake
 
Joined
Sep 29, 2011
Messages
22
Re: Whats Wrong with my 78 Johnson?

Well that is good and bad i suppose. any idea where to start with the carbs? I have the manual and enough skill to diagnose/repair it. is it likely that gummy gas residue has clogged needle valves?
 

fishman204

Seaman Apprentice
Joined
Jun 2, 2013
Messages
43
Re: Whats Wrong with my 78 Johnson?

get rebuild kits and carb cleaner.Also check fuel lines they r old
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: Whats Wrong with my 78 Johnson?

Engine running via the fuel primer solenoid = fuel is being injected directly into the intake manifold. This indicates that fuel is not flowing into OR thru the carburetors... clean and rebuild with kits. Be sure to clean the high speed jets that are located horizontally in the bottom center of the float chambers (2 to a carburetor). Best to manually clean with a piece of single strand steel wire as solvent just doesn't do that job properly.


(VRO Pump Conversion To Straight Fuel Pump)
(J. Reeves)

You can convert the VRO pump into a straight fuel pump, eliminating the oil tank and VRO pump warning system, but retain the overheat warning setup (and fuel restriction warning if so equipped) by doing the following:

1 - Cut and plug the oil line at the engine so that the oil side of the VRO pump will not draw air into its system. Trace the wires from the back of the VRO to its rubber plug (electrical plug) and disconnect it.

2 - Trace the two wires from the oil tank to the engine, disconnect those two wires, then remove them and the oil tank.

3 - Mix the 50/1 oil in the proper amount with whatever quantity fuel you have. Disconnect the fuel line at the engine. Pump the fuel primer bulb until fuel exits that hose with the tint of whatever oil you used. Reconnect the fuel hose.

That's it. If you want to test the heat warning system to ease your mind, have the key in the on position, then ground out the tan heat sensor wire that you'll find protruding from the cylinder head. The warning horn should sound off.
 
Last edited:
Joined
Sep 29, 2011
Messages
22
Re: Whats Wrong with my 78 Johnson?

Thx guys, and Joe, your help and a manual and I will have this puppy up and running in no time. Oh, and a carb rebuild kit.
 
Joined
Sep 29, 2011
Messages
22
Re: Whats Wrong with my 78 Johnson?

I will probably replace the fuel filter on principal, but is there any chance the filter is plugged enough to let the primer work but not the carbs?
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: Whats Wrong with my 78 Johnson?

All fuel to the engine goes thru the filter first.
 
Top