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I want to remove oil Injection

wintys

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"Twin 1996 250/3.0 Mariners EF

"Twin 1996 250/3.0 Mariners EFI, one of them CC rotation
I want to remove the oil Injection from these two old motors
Just bought this old 31’ foot Fountain and I don’t trust the oil Injection system.
I have been going through and checking out every thing I can think of to get her right before I put her in the water, the motors have good compression and crank right up on the hose (running mixed gas from small tanks for now)
After rotten oil hoses and check valves letting gas back up in to the engine oil tank,
(Not the remote tanks) I just don’t want to trust the oil system to these good old motors.
All seems to be easy to remove until I get to the oil pump, I can’t find a kit to cover the hole and I’m afraid if I remove the pump and pull it out the pump gear and what I’m told a thrust bearing on the end of it may fall down in the engine case.
I don’t wont to just disconnect and plug it and let it run, thinking it may get hot just spinning with no oil.
Has anyone ever pulled the oil pump off of this type of motor?
What might I run in to?
Is there a thrust bearing on the end of the gear?
Is there a seal kit that will cover the hole if I remove the pump?
I know they make kits for other motors
(2. something liter and others)
Sorry to make this so long I would appreciate your thoughts and knowledge.
Thanks Winston"
 
"There was mention of this rec

"There was mention of this recently in a thread onScream and FLy forums. I'd head over tehre, there is soem sort of kit which is a blockoff plate and a pin or similar. Getting rid of oil injection on older engines is a very wise idea.

Regards, Andrew."
 
"All the scream and fly folks

"All the scream and fly folks can tell me is how to remove the pump on the older 2.5 motor.
In need info on the 3.0 it has a little different system.
Thanks for the info, if you can think of anything else please let me know, I really want to get this stuff off my motors with out losing a thrust bearing in the case."
 
"Winston, instead of going the

"Winston, instead of going the cost and bother of completely removing the oil pump(s) and putting on plates. You could leave them in place and disconnect them.

You can simply connect the inlet and outlet on the oil pump with a small piece of tube (which will keep the cooties out and let the oil pump run along doing basically nothing) and then either remove the Y connection all together (that feeds the oil to the fuel line) or simply plug it off and run mixed gas.

I would fill the connecting tube with oil just to keep the pump itself lubed. Then if the drive gear failed or the pump stopped pumping, you would never even know (or care).

The pump sitting on the engine (disconnected)will not affect anything...

Here's a diagram of the pump - so just a tube inlet to outlet bypasses the whole oil system...

Additionally, should you decide to sell the engines in future, all the parts are there should the new owner wish to restore the oil injection.

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"
 
"Thanks for your response Grah

"Thanks for your response Graham, The motors don’t really have Y- connection, the outlet hose from the oil pump runs up to the Vapor Separator or what some call the mixing box. I have though about removing the check valves from the oil inlet on the vapor separator and plunging it with a 1/16” pipe plug and re-routing the outlet hose back to the engine oil reservoir and just let the pump re-circulate the oil in the tank, not having to mess with the low oil alarm wiring.
Then plug the check valve from the case to the remote oil tanks with what looks like a 1/2” pipe plug.
I’m not really sure about this vapor separator and I have already replaced the 1/16th oil inlet check valves on it and have replaced the remote oil/air hose to the remote tanks, things seem to work but I still don’t trust the oiling system.
What do you think of leaving the system running like is and mixing my gas anyway 100:1????
Love this site I have learned a lot thanks for all the help?"
 
"You could run both until you

"You could run both until you trust that they are working.

I do that the start of each season with my OMC (VRO system).

Once I confirm that the oil level in the tank is indeed going down, then I stop running premix.

I'm probably one of the minority, but I actually do trust both Merc's gear driven oil system and OMC's VRO2.

Both get blamed for everything from a blown powerhead to hitting rocks and toasting a propeller, but actually, if every engine failure was thoroughly diagnosed, I would bet that in over 95% of the cases it would be found that something other than the oil injection caused the problem. Most often lack of maintenance, improper storage or just plain old "neglect" is what kills most motors.

But it's all about comfort level. If you will sleep better at night by disconnecting or bypassing the oiler, then go for it..."
 
"Thanks again Graham, I think

"Thanks again Graham, I think I will take your advice and run both for a while.
Do you think mixing 50:1 and running oil pumps at the same time will be ok for a while and then maybe drop down to 100:1 later after I see the oil level going down?
I don’t mind fouling a plug; I just don’t want to hurt anything else.
I love this old boat; I drove all the way to the Miami boat show just to dream of this boat back in the early 90s
This site and your help is the best thanks once more Winston
And yea, I heard the oil systems cause running a ground and fish not biting too?"
 
"If you are really nervous abo

"If you are really nervous about the oil injection, running a 50:1 mix as well certainly won't hurt the engine.

It could lead to some extra gunk/carbon in the cylinders and the plugs will foul quicker, but neither of those conditions are difficult to take care of.

If the oil injection works fine you would be running at 25:1, which is the ratio for "breaking in" a new/rebuilt engine - so a bit more smoke - but don't you just love the smell of a 2 stroke anyway?
"
 
"I will only run 50:1 just lon

"I will only run 50:1 just long enough to see the oil going down and then back off.
You have been great help, before I get through with this boat I will probably be calling on you again.
Thanks Graham"
 
"i have found,the best thing t

"i have found,the best thing to do,is remove the pump,slide out the dr gear,reinst pump,using IT as a block plate,then,disc all the above,this way,u do not have that lil dr gear to worry about.
-----I JUST saw his is an efi----i do this on all the rest,.."
 
"JWB, this particular model se

"JWB, this particular model ser.# ranging from 0G129222 TO 0G760299 looks like they have a pressed in bushing or bearing behind or on the out side of the gear shaft, the gear has a trust bearing at the end of it inside the block.
I’m not positive but I think I would have to some how remove or pull out the pressed in bushing (bearing) and thin pull out the driven gear (oil pump gear) and thin I would be afraid that the thrust bearing at the end of the gear could fall off in side of the block right down in to the lower crank main bearing."
 
"The mercury oil injection pum

"The mercury oil injection pump has been very reliable and i would seriously keep it, running oil in the fuel is great until you dont use the boat for 6 months and when you go to start her up the old fuel has evaperated leaving the oil and that has solidified (turned to green jelly) inside everything. It would be an expensive to clean out and replace some components
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"
 
"Thanks Jimmie, Good thought,

"Thanks Jimmie, Good thought, I will only run the 50:1 mix just long enough to tell if every thing is working, but I will probably still run a 100:1 mix after that and keep a eye on it. After studying the system and looking and working on it there are just too many things that can go wrong and cost me a power head that I can’t afford.
I may thin it out before I put her up for the winter and crank and run on the hose every two or three weeks.
Thanks again for everyone’s help and in put, I’m learning a lot here and I just love working with this old boat.
My girl friend hates it and says the boat is taking her place.
I’m going to miss her; I think I got a biiite"
 
"Biiiite back mate!!!! BITE BA

"Biiiite back mate!!!! BITE BACK!!!
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It's good to run her on a hose at least once a month, for a good few minutes at least. From idle up the range, but not more than about 3k. Not a good idea to over-rev without load on the prop...

Although this is not always possible due to chilly weather conditions...
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Besides, the boat has not taken her place, could be a matter of HER being in the way. Gotta go now, I hear my wife coming down the passage cocking the rifle...

I'm outta here!!!

Enjoy buddy!"
 
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