johnson 150 hp v6 vro 1985 octane question

[JLRos]

I know that octane issues in this site had been debated long and passionately but i fail to find an specific answer to my dilemma. I have a Johnson 150 hp v6 VRO 1985 outboard that is running fine, just recently i got the Clymer service manual and it says quote:

1973-1985 135-235 HP-Lead-free regular,
lead-free premium, leaded regular, leaded
premium or gasohol with a pump posted octane
rating of 91 or higher. If a pump posted octane
rating of 88 is used, the maximum spark advance
must be reduced 4 ? except on 1983-1985 150 XP? and GrM
models. If a pump posted octane rating
of 86 is used, consult your local dealer as engine
modifications must be performed in addition to
reducing maximum spark advance.

Questions:
Does this means i've been messing my engine for the past year using 87 octane? (hey is running fine, so far)
Should i disregard this omc recommendation since it was done previous to the advent of TCW3 oil?
TCW3 oil actually make a difference?
Does gas differences on gas additive from 85 to 2013 will make a difference?
Should i'll spend big money and time taking this old but reliable engine to a certified dealer for the so call engine modifications to continue using cheaper 87 gas?

Thanks in for your responses

 

[NYBo]

Re: johnson 150 hp v6 vro 1985 octane question

Welcome to iboats!:welcome:

The issue with octane is preventing preignition under load, which can do bad things like melting pistons.

The type of oil you use won't change this; you need to use the recommended octane. However, there is more than one way to measure octane. If the numbers in that manual are RON (Research Octane Number), you are in luck Octane ratings in the US and Canada use the average of RON and MON (Motor Octane Number), and are 4 or 5 points lower than the straight RON number.

 

[kenmyfam]

Re: johnson 150 hp v6 vro 1985 octane question

Firs issue was getting a Clymer manual.
Have an 85 140hp that has been running on regular gas and TCW-3 oil for many years with no issues.
Just my experience though and also my findings of Clymer manuals. They make very expensive toilet paper.

 

[metriccrescentwrench]

Re: johnson 150 hp v6 vro 1985 octane question

ill make a difference?
Should i'll spend big money and time taking this old but reliable engine to a certified dealer for the so call engine modifications to continue using cheaper 87 gas?

Spend just a little money and get a real factory manual, they're typically on ebay for somewhere around $30 or $40. For all the engines in my small collection (ranging from 1981 to 1993) the factory manual lists regular unleaded (87 octane) with up to 10% ethanol as an acceptable fuel.

 

[JLRos]

Re: johnson 150 hp v6 vro 1985 octane question

Thanks a lot guys, for the prompt responses. Reading what you wrote has ease my worries. Still looking for the original manufacturer manual.