Oil injection or pre mix.....?

flanker7

Member
Mar 31, 2011
267
138
kingston wa usa
Name
Tev
Boat
" The grocery getter" 18ft 1996 Truline CC, Unnamed 2002 Hewescraft 179
i have a 1993 Johnson VRO 70hp 2 stroke that I've finally got running top notch. Bought a new boat project and planned to move the motor to it. New boat has an in the floor fuel tank with the fill cap located horizontally. Not real excited to have to add oil before pumping gas and hoping that I got the mixture right. The engine has an oil injection pump as part of the fuel pump but is capped at the fuel intake port. Original owner said his machanic didn't trust oil injection. I'm toying with the idea of hooking it back up to make filling up easier. Currently using a top side tank so premix is no biggie.
 
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Fishbones

Your wife thinks about ME
Nov 7, 2005
8,468
689
58
Chula Vista
Name
Rich
Boat
One Off 28' Custom Built Skipjack (SOUTHWESTERN) & 18' Sylvan (Short Runs)
I would keep running premix on that motor, just use a funnel to add oil
 
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cortezpirasea

Pangero
Feb 23, 2012
2,189
2,219
la mesa, ca
Name
Russell
Boat
21 ft panga Sea Moan/17 ft gregor Pirasea II
X2 on the pre-mix.
 
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flanker7

Member
Mar 31, 2011
267
138
kingston wa usa
Name
Tev
Boat
" The grocery getter" 18ft 1996 Truline CC, Unnamed 2002 Hewescraft 179
Has anyone had an oil injection unit fail? Honestly I like the idea of knowing for sure that my mixture is right by mixing myself but my marina just put out a policy saying no fueling from containers. Some jackass spilled diesel everywhere trying to fuel up a huge cabin cruiser so now everyone has to go to the fuel dock
 
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colemans224

Member
May 28, 2008
586
264
SoCal
Name
Tim
Boat
seaswirl cc
My brother has an early 90's Johnson 50 2 stroke and the oil injection screwed us a couple times on the lake. By passed it like the previous owner did on your motor and haven't had a problem since. Badass motors those old 2 strokes are. Maybe premix your fuel in a 5 gallon can? that way easy to keep the proper mix ratio.

Edit: Damn, just read your post about no mixing from containers. That sucks.
 
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mike garrahan

TheSabreGuy
Sep 7, 2007
2,077
2,304
la habra hts
Name
mike garrahan
Boat
23 ft. crestliner
Three years ago we blew up a 175 hp Merc when the oil injection stopped working and I couldn't hear the alarm because of engine noise and my poor hearing. It ended salmon season early for us and cost a lot of money for a replacement motor. Now we always premix. I will never trust oil injection again. Do a search on the internet. You will find tons of horror stories caused by oil injection failure.
 
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flanker7

Member
Mar 31, 2011
267
138
kingston wa usa
Name
Tev
Boat
" The grocery getter" 18ft 1996 Truline CC, Unnamed 2002 Hewescraft 179
Well that's some pretty compelling evidence. Maybe I'll just pump gas in 5 gallons then add oil until it's full. I worked to damn hard to get this motor running right.
 
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tj805

Member
Jan 26, 2012
326
95
Los osos
Name
Tony
Boat
19 arima sea chaser 12ft Livingston
I have a 1987 Yamaha 90 hp precision blend
It's oil injected and I've never had a problem.
I had a buddie with a 175 and his alarm went off and the motor went into limp mode.
My local Yamaha mechanic says ( run it)
Said the Yamaha oil injection system is really bulletproof.
He also said the Johnson / mecercy oil injection systems are not so hot.
My theory is why cap it off it it's working as it should.
 
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tanner.s

Fish Slaughterer
Oct 18, 2012
1,896
599
San Diego
Name
Tanner
Boat
1997 Proline 23 W/A
Just add fuel to the tank first but don't completely fill, then add oil based on how much you pumped. Easiest thing I can think of.

Sent from my SM-G925V using Tapatalk
 
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polfishski

I Should Upgrade My Account
Oct 5, 2008
2,006
422
Descanso
Name
Tom
Boat
20 SkipJack (Tail Chaser)
I opened up an older 175 that had fried one piston the oil injector tube has a small screen that was plugged. The original system had the filter in the main tank removed so crud was able to get into the pump. If you have any doubts to the service history I would pre mix the oil,repairs are far from cheap.
 
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