My 1987 90HP was converted to a 2 cycle, I want to convert it back - how to?

[frankk]

OK, I will admit that I am not a mechanic (but love to learn) but do know my way around my Merc 5.0 / Alpha One.
I have a 90HP Johnson 4 cycle that was converted to a 2 cycle, having now to mix 50:1 gas. It was done maybe 10 years or so ago, and although it runs strong, it still smokes like a 2 cycle. On top of that the bottom end is leaking quite a bit causing it to overheat at low idle. I would like to convert it back to a 4 cycle, and understand that might not be easy. Cannot seem to find any info on the net on how to.. I do think that if I convert it back to a 4 cycle some of the smoking will go away and maybe fixing the leak will stop the smoking and the overheating will go away. Here is the link to the leaking. Look to the left of the muffs. That vertical line is actually water leaking out when I was running water with the muffs on. http://electronicinstrument.com/pee.jpg I do think that I would want a mechanic to do this work for me though. Other then that the motor works well. Any thoughts or suggestions?

 

[Joe Reeves]

Re: My 1987 90HP was converted to a 2 cycle, I want to convert it back - how to?

The 1987 90hp Johnson was always a 2 cycle engine, and it would be impossible to convert it to a 4 cycle.

Are you speaking of returning it to its original VRO mode setup so that you don't have to mix oil with the gas?

Bottom end leaking?... I looked at the link. That's simply a metal to metal fit and that leakage wouldn't cause the engine to overheat.

 

[frankk]

Re: My 1987 90HP was converted to a 2 cycle, I want to convert it back - how to?

Hi Joe, yes I guess that is what I meant. If I do that is there a good chance it would not smoke as bad? On the leaking is that something I can tighten up?

 

[F_R]

Re: My 1987 90HP was converted to a 2 cycle, I want to convert it back - how to?

Well, the VRO does run a little leaner on oil at certain speeds. But it is still gonna smoke. If it bothers you that much, switch to 100% Synthetic outboard oil (NOT car oil). Even part synthetic will cut the smoke some. But neither will COMPLETELY eliminate the smoke.

The leaking at the seam is normal and harmless. Don't pay any attention to that. Any water coming out there has already gone through the engine and done it's job. However, it shouldn't be overheating at any speed. That is serious and should be dealt with immediately. Start with a new water pump.

 

[frankk]

Re: My 1987 90HP was converted to a 2 cycle, I want to convert it back - how to?

OK, thanks, it was odd. WHen I had the hose running into the muffs, all was ok but when I poured say almost a gallon of the winterizing, non-corrosive stuff into the muffs, the engine was peeing but after about almost a gallon, it stopped and of course.. the alarm went off. Will start on the water pump then. THanks

 

[kenmyfam]

Re: My 1987 90HP was converted to a 2 cycle, I want to convert it back - how to?

What were you pouring in there ??? Outboard just needs to be stored for winter vertically and fogged through the carbs / air intake.
Suggest you review some of the "Top Secret Files" at the top of this section. As previously sais your motor was never a 4 stroke. The old VRO pumps varied the amount of 2 stroke oil going into the motor depending on the usage. Pre mixed fuel should be at 50 to 1 ratio. The replacement pumps for the VRO are called OMS and feed the motor with a constant 50 to 1 ratio as well.

 

[Joe Reeves]

Re: My 1987 90HP was converted to a 2 cycle, I want to convert it back - how to?

Outboards have all of the water drained out automatically... there is no water left in the engine so do not be running any antifreeze or whatever thru it. The water pump and the engine's cooling components are designed to work with water only.... whatever you've been running thru it may have damaged the impeller.... maybe.

The fuel mixture is to be a 50/1 mixture.... I suspect you are using someother mixture. 50/1 is "1 pint" of good quality 50/1 oil to "6 gallons" of gasoline. A gasoline rating of 87 will be fine. Do not use any other type oil!

No offense intended here but it sounds like you have no knowledge of the engine or outboards in general at all. If you intend to keep the engine, it would be a good idea to obtain a service manual for it, and if possible.... to personally become acquainted with someone in your area that can guide you with their knowledge to have you avoid expensive mistakes.

We, the members of "iBoats" will of course do what we can from this end.

 

[steelespike]

Re: My 1987 90HP was converted to a 2 cycle, I want to convert it back - how to?

A leaky fuelpump diaphram may cause excess smoke.
50:1 fuel mix is 2.6 ozs per gallon.You wouldn't notice the difference if you were a little over that.
The motor will seem extra smokey on the muffs.
How did you introduce the "winterizing stuff" into the muffs seems like the pump could have lost its prime and they are not self priming.
If you don't know the age of the pump it should be replaced anyway.