Have a 1997 Mercury 175. I am thinking about disconnecting the oiling system and going with pre-mix but have read about guys changing to Electronic Oil Injection after market systems. Has anyone here done this and how did it go and what was your cost?

Thanks

AJ

I had a Evinrude that oil injection went out on it and after spending a grand and it not working and the repair shop wanted another grand to try and fix it a second time. I decided to disconnect the alarms and mix oil in fuel. It worked very well...

ya just take the oil pump off and you have to put a plate on the block where the pump goes. then premix and your care free after that!!

if you disconnect the oiling system on anything but a johnson or evinrude you will hurt the value when you go to resale. the merc and yamaha oiling systems are very dependable .

I have a 99 225 EFI and went to premix and have had no problems. MAKE SURE you put the 50:1 Ratio premix mercury premium plus oil in the gas. I say Premium plus because that is what I use. You can use any TWC oil I guess. If you do go premix You will want to get a mecury oil injection block off KIT!! because there is a plastic gear that turns the pump. If you don't replace this gear with a dummy shaft there is a possabilty that the gear will shred if left in the motor OR! if you just leave it empty there is a bushing that holds the end of the shaft ( gear ) that might work its way loose and become lodged in the engine and tear the motor up inside. Just a thought.

+1 on the dummy shaft. The shaft is installed to prevent the brass bushing from dislodging and destroying your engine.

The plastic shaft also takes up space, or stuffs the void where the steel shaft was. If the void is left open (blank plate used instead of plastic shaft) that cylinder becomes lazy due to increased crankcase volumn and as mentioned, the brass bushing can work it's way out and cause major destruction.

Here's what I've learned about oil injection after working on outboards since 1982:

At idle the fuel is mixed at 100:1 right into the bowl on the carb or into the VST on an EFI. This is great when at idle but by the time the motor gets up to 6k it needs 50:1 and it ain't there. The pistons are right on the verge of gaulding when the oil mix gets to 50:1. How many times can a motor endure this kind of abuse before it fails? Who drives like a grandpa? No one I know. Mercury Engineering gets a big fat "FAIL" for that one.

2nd note while we're on the subject of oil injection, the plastic/nylon (not sure of spelling of actual material used so we'll go with that) gear used on the crankshaft is not the guilty culprit when a failure occurs. You automatically assume it is when you see the gear damaged, but in reality it's the brass bushing that causes the train crash. The brass swells from excess heat (several things cause this) and binds on the steel shaft which in turns slows the shaft down and puts a greater pressure on the nylon gear causing shearing of the nylon. Mercury Engineering chose to use a nylon gear to prevent internal damage should a steel gear fail.... and when the nylon gear fails it causes what, slight damage???

1997, sure, take it off and pre-mix. Don't go ta any add-on type oil injection. They suck. As far as Merc's stuff, its good to a point. Gettin' old or a lotta hours, take it off. Twistin' a bunch of rpm. Take it off. Here's tha best part. Overheated, neglected motor. Take it off. Tha last part is 99% of failures but tha gear gets tha blame. There's WAY to many out there that's still makin' smoke ta generalize its a BAD system. But like any other part on tha motor. Stuff wears out. Again, if its old and/or you don't know tha motor history, get rid of it.

Do you really think Merc would keep puttin' a bad system on a motor thats gonna turn 6750 with a warrenty?......JMO

The two most common complaints to Mercury are oil injection failure and ring locator failure. But if you look at the percentage of failure it's rather small when you look at the total built. According to a Mercury Tech it's less than 3% under warranty (they must have built a gazillion).... not a bad system when new, but like you said, age and elements...

There seems to be a common denominator when it comes to failure--- age. Everything we see come through the shop with a sheared crank gear is over 10 years old. Another failure is caused from control modules, so they go bad as well.

I have an '84 200 (1st year of the oil injection) on a Baha ski boat with over 2000 hrs and never had a bolt turned on it. It's been on several bass boats as a loaner and made a few blasts down the river on the Hydro and it just keeps on going and going.