88 90 hp oil injection removal

[maxthedog]

Hi All
I have an 88 90 hp and would like to remove the oil injection (I don't trust it). The motor has the oil tank mounted on the port side, the pump and mixing chamber on the starboard side. Can I just bypass the injection system and run mixed gas into the gas line? Do I need to remove the oil pump? How about the hose running from the mixing chamber into the side of the block?

 

[JoeMan]

Re: 88 90 hp oil injection removal

I have a 1995 oil injected Merc OB. My understanding is that Merc oil injection systems are the best out there. Why do you want to remove or bypass it? Think it's not working properly? A mechanic can measure the intake of oil from your system if you're not sure.
For some, it's just due to worrying that "if" it ever breaks down that you won't catch it in time. But folks also burn up their powerheads by neglecting to add oil to the gas too. Oops!

 

[Raghauler]

Re: 88 90 hp oil injection removal

Joeman, Max may be on to something... your vintage is good, however, Max is in my school. I have a 1987 115 I-6. I was told it wasn't a matter of "if", but more a matter of "when" my mixer will fail.

Max, I don't know anything about your 88 90, but I can tell my Merc has "oil injected" written on it, but it really utilized a mixer system, and not an injector system (I have 3 carbs, not fuel injection). For me, my engine sees the same 50:1 whether my mixer delivered it to the carbs or if I mix it manually in the tank (what I do now). If yours is truly an oil injected system, diregard my advise:

My oil resevoir was a part of the pump... I disconnected the pump and connected the tank directly to the engine (with a primer bulb in-line) after purging the tank of all "straight" gasoline. I also simple disconnected the electrical lead from the engine (and alarm) to the pump... no jumper wires needed. I mix 50:1 as I fill the inboard tank... not super convenient, but one less thing to worry about out on the water with an otherwise reliable and VERY old outboard. Good luck.

 

[phatmanmike]

Re: 88 90 hp oil injection removal

remove the pump and replace with a block off plate from your dealer. also replace the oring under the plate.

block off the oil line with a cap so it doesnt suck air. the rest is up to you. i completely took all mine off.

i also removed my oil injection alarm and sensor