Living on borrowed time with VRO?

[powrguy]

I've got a Mariner 135HP Mariner, 1988 vintage, that still runs the VRO oil-injection. It's been fine, runs well, etc., but am I running on borrowed time awaiting an oil-injection failure and risking a blown engine? Right now, the engine's hangin' from the lifting eye on my engine hoist in the garage, and I was going to clean and re-gasket the carb's, rebuild the fuel pump, swap the tilt/trim unit with a unit I got over the winter and cleaned, tested, and painted, and also going to drop the lower unit to rebuild the water pump. While it's off the boat, there's cosmetic work to do on that, too, and I'm wondering if I should just cap off the oil-pump, and pull the oil tank and lines out of the boat and just go to pre-mix.

It's real convenient to just pump gas in the tank, and not have to pre-mix, but I don't want to have a failure and blown motor during the season, either.

What's the sense of the experts here on the Forum?

thanks

[jody504]

You can clean the oil tanks out good and change the hoses.You can even get a new pump and install on the motor.It becomes a thing of how much you like oil injection.Does Mercury have a good system.Most don't take the time to Mantain it to make it good.I have alot of coutmers that don't want the motor without it they love it.If I go in there motor I replace everything with the system and they run it.Most all proplem come from contaminaded things in the tank be it water peices of oil bottles,when this happens the pump locks up then it strips the gear on the crank.Everyone blams the plastic gear but most of the time there is a reason the gear goes. Again it a matter of what you like.I dn't have it on my motor but I only have a small tank if you have a big tank oil injection is nice

[Rude Runner]

Replace the plastic bushing connector with the magnet in it just behind the oil pump. That is why Merc had tons of their oil gears on the crank fail. It was made twelve thousands to big and when heat and oil cause it to swell it would seize up in the bore. Even today Mercury will not advertise that fact for fear of the largest lawsuit in history but I have been told that is what the problem is many times by Merc service reps. That is also why they ditched the plastic bushing and went directly from the crank gear to the pump with a longer stainless shaft gear and a brass bushing. It works so well that they had the balls to remove the oil motion warning sensor. All new plastic original type bushings are made the correct size now so just replace it and you will be good.

[powrguy]

I'm trusting the system, as it is on a Robalo CC boat and the 65 gallons of gas only is easy to fill when there's no premixing. I plan on checking ALL the fuel and oil lines, and re-wiring my center console, too, so the oil tank can be looked at pretty closely as it will be moved out of the way for wiring anyway. I also am going to empty the fuel tank, check for water/debris/etc., and changing all the filters from the pickup to the motor itself. I am one who sure likes the VRO, and have had zero problems, but just thought I'd see what others think.

thanks for your input.

[powrguy]

Replace the plastic bushing connector with the magnet in it just behind the oil pump. That is why Merc had tons of their oil gears on the crank fail. It was made twelve thousands to big and when heat and oil cause it to swell it would seize up in the bore. Even today Mercury will not advertise that fact for fear of the largest lawsuit in history but I have been told that is what the problem is many times by Merc service reps. That is also why they ditched the plastic bushing and went directly from the crank gear to the pump with a longer stainless shaft gear and a brass bushing. It works so well that they had the balls to remove the oil motion warning sensor. All new plastic original type bushings are made the correct size now so just replace it and you will be good.

I'm not sure what part you're describing. Do you pull the oil pump to change this bushing, and does the shaft of the pump run through it?

[Rude Runner]

Remove the two 5/16 head screws on the oil pump (bottom port side of the engine) carefully move the pump out of the way and remove the plastic Grey bushing behind it that is still on the block bore. Don't panic if the shaft comes with it, Simply screw it and gently push it back into place when you get the new one. Its a worm gear shaft. The bushing is basically a coupler between the stainless shaft and the pump.

[powrguy]

Okay; got it. I know what you are referring to now. I'm gonna order the part from Crowley Marine, I guess, and then change it out.

Thanks for the help !

:cheers:

[Rude Runner]

http://www.mercurypartsexpress.com/us/index.php?target=my_machine_detail&mode=view&machine_id=401291

#9 is your bushing, your replacing with a new oring so it dont leak.

[Rude Runner]

Anytime, Don't forget the oring on the back of the pump and you should get some of the clear hoses that go to the pump for incase they need to be replaced. If they are old and brittle they can leave you stranded.

[FlatSleek]

Replace the plastic bushing connector with the magnet in it just behind the oil pump. That is why Merc had tons of their oil gears on the crank fail. It was made twelve thousands to big and when heat and oil cause it to swell it would seize up in the bore. Even today Mercury will not advertise that fact for fear of the largest lawsuit in history but I have been told that is what the problem is many times by Merc service reps. That is also why they ditched the plastic bushing and went directly from the crank gear to the pump with a longer stainless shaft gear and a brass bushing. It works so well that they had the balls to remove the oil motion warning sensor. All new plastic original type bushings are made the correct size now so just replace it and you will be good.

Do you know what year Merc upgraded the pumps, I was wondering if my 2000 ProMax 300 should be done, Thanks.

[JR IN JAX]

Great info,
I love my OI system and want to keep it.
Thanks Much.

[Rude Runner]

Do you know what year Merc upgraded the pumps, I was wondering if my 2000 ProMax 300 should be done, Thanks.

Send me your serial number in PM and I will have a look because I think your good but cant remember for sure when they did the fix, It may have been 2001.

[wideglide55]

2000 PM is a brass oiler gear,never heard a bad word about one,my 99 had over 200 hrs no issues and still runs perfect.Most of the hrs. were at full throttle.Keep your injectors clean,change the fuel filter twice a season and always run fresh fuel and 300ProMax run long long time

[1BadAction]

**** oil injection.

it's caused more failures than it has prevented. The only thing you need to know about the oil injection on a 2.0/4/5 based motor is how to bypass it and throw it in the closest trash can.

No clue how the 3.0L motors got brought into this convo :nonod:

[Rude Runner]

**** oil injection.

it's caused more failures than it has prevented. The only thing you need to know about the oil injection on a 2.0/4/5 based motor is how to bypass it and throw it in the closest trash can.

No clue how the 3.0L motors got brought into this convo :nonod:

Some got lucky like my bud who spins his hard to 7000rpm at times for 16 years and never had a failure but most pop because of a $17.00 Bushing.

Merc has known about the problem for many years, Still today if you have a failure they recommend you spend over 400.00 to replace the whole oiling system besides the damaged power-head. Pretty crappy when they know it will only take a Bushing to remedy the problem. I have never seen a merc oil pump fail, As long as its being driven by that bushing its good.

[frogII]

subscribed;
mines an 87' 135 most likely the same thing

does anyone have a part # for block off plate and other needed info
just in case

[Rude Runner]

subscribed;
mines an 87' 135 most likely the same thing

does anyone have a part # for block off plate and other needed info
just in case

Pro Marine makes a plastic one with an oring that was originally for the Yammys but it will work nicely. Locktite the screws in and I would even put some Locktite Gel seal around the sealing surface as well. Pro Marine has all that.