# 1985 70HP Evinrude VRO



## RAMROD (Jan 29, 2013)

Bottom cylinder 120
Middle cylinder 120
Top cylinder 105

Was told the motor was blown when I bought it. Figured I would just try it out and it fired right up and ran good! so I then checked the compression got the above readings.

Got the boat dirt cheap due to bad motor, so what do you guys think?


----------



## lckstckn2smknbrls (Jan 29, 2013)

Do a de-carb on it then see if the readings change.


----------



## RAMROD (Jan 29, 2013)

lckstckn2smknbrls said:


> Do a de-carb on it then see if the readings change.


OK would you use seafoam or what would you recommend to use.


----------



## lckstckn2smknbrls (Jan 29, 2013)

In a 1 gallon gas can mix your fuel with 3/4 of a can of sea foam. Run the motor while spraying the last 1/4 can of sea foam into the carbs. It's going to smoke a lot. Shut the motor off wait about an hour then start it up again it's going to smoke a lot more.


----------



## RAMROD (Jan 29, 2013)

OK will give that a try.


----------



## RAMROD (Feb 2, 2013)

Ok well it's done. Have around 125-130 in the bottom two and still 100-105 in the top when cold. When the motor is warm the numbers drop to around 110 in the bottom two and 90 in the top. Not a mechanic so not sure why there is a big difference between hot and cold readings. It also doesn't seem to idle as smooth as beforehand but It still seems to run strong.


----------



## JoshKeller (Feb 2, 2013)

was it still smoking after you ran it after doing the decarbon with seafoam?


----------



## RAMROD (Feb 3, 2013)

It was not smoking very much to begin with I would say normal and still about the same. Think I should do it again?


----------



## LA_Gas_Man (Feb 10, 2013)

You can pull the head and look at the cylinder in question to see if there are any gouges or scoring in the cylinder. If you don't see any damage I wouldn't worry too much about it, just decarb it some more.


----------



## RAMROD (Feb 10, 2013)

Put in the water and it ran way different. Put it in gear and it would die then it was a pita to get it fired back up. Got it to run enough to plane out one time then it died and would crank back up. Glad I brought the little 4hp to get back to the dock. When I made it home it fired off and ran like a top.


----------



## LA_Gas_Man (Feb 11, 2013)

I would go ahead and pull the carbs off and clean them real good. The seafoam may have broken some trash up and possibly clogged up a jet.
After that run it for a few minutes then check the compression again.

*DISREGARD* See my next post.


----------



## LA_Gas_Man (Feb 11, 2013)

Is the VRO still hooked up or do you premix? If that cylinder is running with low compression it can make the motor run like crap out on the water while running under a load, BUT it may run fine at home on the muffs.

I had a Merc 150 V6 that had one cylinder w/low compression. It ran great on the muffs. I didn't run it under a load for fear of causing the piston to break apart or throw a rod through the block.
I had HOPED it was just a stuck ring and decarbing would free it up. The compression never came up so I tore it down. The ring had welded itself to the piston and gouged/scored the cylinder wall. This was from the previous owner not doing any preventative maintenance, had a clogged jet in one of the carbs which caused it to overheat.

If I were you, like I had previously posted, take the head off and check that cylinder before running the motor anymore. If the low compression is from a damaged ring, piston, etc., the damage WILL get worse by running that motor.
If you don't notice any damage you can pour some seafoam or "ring free" on top of the cylinder, let it soak for a day or two, and see if it may just be a stuck ring. BUT if it WAS a stuck ring I would think that your recent run on the water would have broken it loose.

So go ahead and check compression again. If it still low then pull the head. If the compression reading is higher than before, then it may just be a stuck ring.


----------



## RAMROD (Feb 11, 2013)

Yes the VRO is still in use. If I fix this motor it will be plugged off and I will pre-mix. I just acquired an 83 Johnson 75hp on another project. Compression good all around, motors look identical except where the electronics are located and the 75hp is a pre-mix motor. All on hold for now though headed back in for three weeks of work. Thanks for all the tips! I will be pulling the head on this thing to take a look and tinker with.


----------



## ShipwreckStew (Feb 20, 2013)

I just bought a 1986 60hp Evinrude VRO and the whole VRO pump was bad. Instead of putting a new VRO pump on and blocking it off to run premixed fuel, I put an older (1982) fuel pump on to get rid of the whole VRO system. The part was way cheaper than a new VRO pump and I know for sure that my engine is getting the correct ratio of oil


----------



## Paul Marx (Feb 21, 2013)

That's an old motor . If it were me I rebuild the top end and block off the VRO.


----------



## nick4203 (Feb 21, 2013)

i have an 81 kz 1000 and i had one cylinder that was running ~70 psi i poured in some seafoam and let the cylinder and and piston soak in it for mabe 3 days brought it up to a 100psi after running it a little bit in idle 

i love seafoam this stuff really works


----------



## RAMROD (Feb 21, 2013)

Thanks for the tips! Plan on pulling the head when I make it home. Will take some pictures when I do.


----------

