Merc oil injection

[Rod1]

I have a 1994 200HP 2.5L Offshore. The oil injection system quit working so I pulled the pump. It appears Ok and the shaft is not sheared. Further looking leads me to believe that the worm gear that drives the oil pump shaft is made out of plastic and has failed. Is this the common failure mode for this system?

 

[Laddies]

Re: Merc oil injection

Yup!

 

[wilde1j]

Re: Merc oil injection

You will usually see shards of black plastic on the business end of the driven shaft when the crappy gear fails.

 

[Rod1]

Re: Merc oil injection

Yup!

Thanks, I thought so. Next question, is this a DIY mechanic job?? Working from the carbs in? Also is there a better quality than the factory plastic??

 

[Rod1]

Re: Merc oil injection

Thanks, I found those shards. After I figured out they were plastic, that really had me puzzled. You don't find plastic parts in the key engine components of a 200 HP automobile so why an outboard??? Planned obsolesence!!!
As I asked Laddies, is this a DIY mechanic job?? Working from the carbs in I assume??

 

[Garrett's Daddy]

Re: Merc oil injection

My 89 175 had oil injection, Mercury has a history of failure on these components. My understanding is the biggest culprit is the fiber gear on the crank as it dissintegrates. The manufacturer provided you with a nice warning device...your motor seizes when the oil injection fails, if yours is running, you sir, are lucky. I was fortunate enough to get a rebuilt 200 head for $2500.00, I though it would be worse. the kit to remove the oil injection components were about 40.00, this is a common kit. I now add oil to the fuel and breath easy.

 

[Tadd_P]

Re: Merc oil injection

Just mix your gas that simple. Problem solved. Oil injection is pure laziness and almost sure to fail at some point.

 

[gss036]

Re: Merc oil injection

To answer your question, NO! it is not a do it yourself project as the enginge has to be torn down to replace the plastic gear. Just mix 50-1 after you have installed the kit needed to remove the injection system.

 

[Rod1]

Re: Merc oil injection

Thanks gss036 I was afraid of that. Kinda leaves a sour taste in my mouth for Mercury--- I wounder how many little plastic parts they have floating around in the high $$$ Verago's???

 

[studlymandingo]

Re: Merc oil injection

Oil injection is pure laziness and almost sure to fail at some point.

Oil is injected at a varied rate according to engine RPMs, you don't need a 50:1 ratio at idle speeds. Oil injection makes good sense, uses less oil, smokes less. There is a motion sensor on the pump that warns you if the pump fails; they are really pretty reliable systems.​

 

[jrenard]

Re: Merc oil injection

I have a 1989 Merc classic 50 that was recently serviced and the mechanic told me to have the unit pulled. He indicated that Mercury has warned of too many failures and that they are "accidents waiting to happen". Mix it in the tank.. easy fix.

 

[MercGuy]

Re: Merc oil injection

So is this a problem that affects certain models & years ?

I have a 1998 115 with 700 hours on it. Never had a problem, runs like a champ.

I would hate to have to worry about the oil injection failing, and I never want to go back to mixing oil & gas ever again !!

 

[jrenard]

Re: Merc oil injection

What I was told by the dealer is that Mercury has informed him to "pull them from the systems" as they come in. I guess they have just had too many problems. I am not sure what year they stopped putting them in, but he said there was a reason why they stopped employing the oil injection systems.

 

[MercGuy]

Re: Merc oil injection

What I was told by the dealer is that Mercury has informed him to "pull them from the systems" as they come in. I guess they have just had too many problems. I am not sure what year they stopped putting them in, but he said there was a reason why they stopped employing the oil injection systems.

Huh ? Something isn't right here. Merc has in no way stopped employing oil injection systems.

Of course I instantly became suspicious when I read "What I was told by the dealer..."

 

[jrenard]

Re: Merc oil injection

Clarification, my understanding was for this particular reservoir system. I am not sure what years are inlcuded, but he indicated that 1989 was one of the last years for this type of remote tank system.

 

[yamamarinetech40]

Re: Merc oil injection

I'd believe just about anything....about Mercury('Setting the water on Fire')....but I think the grapevine may have gotten something a little out o whack on that...nobody think less of merc's oil inj. than me, i imagine, but that sounds odd...

 

[rainman5]

Re: Merc oil injection

My brother has a 1988 Merc 35HP that had the oil injection system, He was also told the best thing he could do for that motor was do away with the injection unit and mix his oil and gas himself.

 

[Cape Coder]

Re: Merc oil injection

I have an 1985 60 HP and I too had to switch over to mixing oil w/gas.

 

[zzzzz]

Re: Merc oil injection

Merc to this day still uses a plastic oil pump drive gear...?why-who knows but I have seen a time when we had 6 blown V6 Mercs on the shop benchs at one time....hard cold start-pump-pump-pump-the motor starts and with all that fuel shoots to 6000 RPM and there goes that piece of plastic !

 

[fabricator]

Re: Merc oil injection

Oil is injected at a varied rate according to engine RPMs, you don't need a 50:1 ratio at idle speeds. Oil injection makes good sense, uses less oil, smokes less.​

Oil injection systems are a great IDEA, too bad they are as unreliable as they are and the result of their failure is a seized engine. If you want less smoke and you're mixing it yourself, use Amsoil 100:1, I have for years.