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Johnson 90-HP: General Reputation
|Author||Topic: Johnson 90-HP: General Reputation|
posted 03-23-2004 12:59 PM ET (US)
I have an oppurtunity to purchase a nice 80's vintage Montauk with a 1991 Johnson VRO 90 hp engine. I prefer to buy a boat with a Yamaha engine but came across this one and am not very familiar with the engine and thus am a little skeptical. Is this a reliable engine? Does it have a good reputation? It appears to be very clean and reportedly runs well. Any input?
posted 03-23-2004 01:17 PM ET (US)
I have a 1994 90HP Johnson VRO. It has been a very reliable engine, and it has a lot of of torque/power. Not the best on gas compared to a new generation, but I can run all day in my Montauk and it will burn about 18 gallons, or so, depending on how fast it is run etc. I would check the compression, change the water pump, the plugs, and lower unit oil and give it a test.
posted 03-23-2004 01:44 PM ET (US)
It's a real work horse with proven ability. Darn things will run forever.
posted 03-24-2004 07:29 AM ET (US)
RWB, The 1980's vintage 90 h/p OMC were some of the best motors. I have one now on the menemsha and may be looking for a back up as it is getting older and tired. If you are not comfortable with yours let me know and maybe we can work something out. I would [disconnect?] the VRO and pre mix my own oil/gas.The last thing you need to worry about is the oil pump stop and not know it (no alarm etc) miles from no where. I have friends that are warranty mechs that tell me as soon as warranty is over on new motors "[disconnect?] VRO".
posted 03-24-2004 08:18 AM ET (US)
Thanks for the comments, I feel more confident in my purchase now. bwmenemsha, I appreciate the offer but will likely use this engine on the boat as I've blown my budget on the purchase! Also, I've heard others echo your comments on the VRO, so I'll take your advice.
I'm really looking forward to upgrading from my '63 sport into the '85 Montauk...a longtime dream come true!
posted 03-24-2004 08:19 AM ET (US)
I have the same engine, just a year younger, a 1992...great engine...before I knew what I had, I was seriously thinking about repowering while things were still running strong on it but after doing a bunch of research on this board and others, talking with various mechanics, etc...I've come to the conslusion that this is a really great engine that will just keep going. When I had mine winterized this last year, I had a few things taken care of...replaced the trim motor, extremely corroded, compression tested, replaced water pump...it's good to go for this year, and many others...more than enough power for my 1989 Newtauk...jumps up on plan in about a boat length! I would not pass up a deal with this engine...great package!
posted 03-24-2004 01:26 PM ET (US)
I love that engine and personaly would NOT disconnect the VRO. If it aint broke....don't fix it. Usually when they go bad, they flood the engine with oil, not starve it.
posted 03-28-2004 09:09 PM ET (US)
Bigshot, I hate to disagree with you at all, but my VRO quit and it starved my engine of oil, and you can guess, burned up #3 cyl. The stupid idiot horn didn't work, and I had no Idea. If I had just taken a few people's advice and premixed it to begin with I wouldn't have had to rebuild. My .02, I will never trust a OMC VRO again. I do love the motor though. Just think that the VRO systems have problems with age.
posted 03-28-2004 09:45 PM ET (US)
The OMC engines with VRO do seem to have a bad reputation. One thing about using pre-mixed fuel is you know the engine is always getting some oil and you know the ratio.
posted 03-29-2004 02:51 PM ET (US)
highly doubt it was the VRO....when you quit injecting oil, you burn ALL the cyls, not one. You had a bad carb and 99% of the time, they blame the VRO. Yes they had a bad rep for the VRO in 1984 when they introduced it but they are now part of the fuel pump. If it quits, so does the fuel flow, etc.
posted 03-29-2004 09:36 PM ET (US)
Bigshot, maybe I had a bad carb,etc..., I'm not sure, I know that the vro pump pumps both gas and oil. I couldn't figure out how the oil quit and not the gas. All I know is it seized and burned #3. After rebuild, I just put stock fuel pump on and mix it, that way I'm sure that it is getting the oil. You think that cylinder was starved and that is why it seized? I'm no mechanic, but I did tear it down and reassemble the motor after I got the bored and assembled block back. I was just told that it was caused by the vro by the mechanic that helped me. Could this happen again if one of the carbs gets gummed?
posted 03-29-2004 09:55 PM ET (US)
I had a 70HP Johnson 1995 with a VRO - which I think is the same setup at the 90HP version.
The thing didn't quit (VRO), it just didn't put out sufficient oil at low rpm. So, I wound up scoring the cylinders. Failure mode on these things is not just a binary on/off sort of thing, they can be deficient in the AMOUNT of oil they pump and it can fool the oil sensor.
I found this out since the motor would chirp at low rpm - occasionally. I had it checked in its spring tune up where the mechanic actually measured the volume of oil that it put out. That's how I found out that I was improperly lubing my engine. I replaced the VRO at a cost of about $500.
Looking into it further, it looked like this engine had had at least one ring job before, so I doubt this was the first time this had happened. It was doubtful that I could do another (or the block could accomodate it). So since I use the boat alot, I traded the motor off in a repower deal.
I think if you use these VROs (the engine is great other than the VRO), a suggestion was made to me to mix oil to 200:1 or so and then let the VRO do the rest to guard against this failure mode. The VRO is primarily a convenience rather than a real performance thing. Anyone smart enough to realize what VROs do should be able to mix the oil properly.
I think this is good advice - I just don't trust the damn things after that. Mixing oil is simple compared to the damage and hassle that can occur in this rather simple VRO/sensor scheme.
posted 03-30-2004 12:28 PM ET (US)
Don't want to get into it but.....if your oil pressure light flickered at idle but your mechanic said it was OK and you ran it and blew the engine from low oil pressure.....how is that the oil pumps fault? The beep states that there is a problem, it was not as if the VRO went bad and blew the engine, ignoring the warning system did.
For the last time and Al-A -Buy can verify this:
WHEN A VRO PUMP GOES BAD IT PUMPS TOO MUCH OIL INTO THE ENGINE. If there is ANOTHER problem with it like a restriction, then the alarm will sound in a few different ways. If one chooses to ignore these alarms, they WILL pay the consequences....but it aint the VRO's fault.
posted 03-30-2004 12:33 PM ET (US)
PS...whalercop....if you did NOT clean the carbs after the rebuild, chances are it will do it again. Stuffing a piston(I just did it)takes a while, sometimes years of a carb running just slightly lean. This could be a bad carb or a vacuum leak, fuel line sucking air, etc. When gas is mixed with oil it is VERY important that it does not run lean. On the other hand if you run rich it will not help in that you will build up carbon, stick the rings and blow a piston that way. Running 40:1 is not insurance on a 50:1 engine, if a carb runs lean, she will still blow if you ran it at 25:1.
posted 03-30-2004 07:07 PM ET (US)
Thanks Bigshot, I had the carbs rebuilt. It has been great. How often sould I rebuild them? Engine is bored .030, can't be bored again, this is it, and I want to make it last as long as I can. Thanks again.
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