Newby questions

[marty_c]

"This is the first boat and mo

"This is the first boat and motor I have owned. I am looking to get a owners manual for the motor but until then.....
1986 Mariner 20 HP, what is the gas/oil ratio, what size/brand plugs are recommended and what is the gap. I'm sure to have more questions as time goes on. Thanks for any input."

 

[galamb]

"Marty, an excellent all round

"Marty, an excellent all round maintenance manual is Seloc's manual for 1 & 2 cylinder Mercury's covering that vintage (use it myself).

Merc's service manual is exceptional but will set you back about 85 bucks if you want to go that way - but is written for marine techs and assumes that you know alot of things - Seloc's will explain in detail with do/don't sections.

However, the service manual is very specific to the 20/25 horse motors while Seloc's covers everything from the little 3.9 horse upto and including the 35's or 40's - so sometimes the diagrams don't look exactly like your model.

Regular unleaded (86 or 87 octane) and TCW-3 rated marine 2 cycle oil mixed at 50:1 is perfect.

Since most gas also contains upto 15% ethanol (alcohol or methanol) it is also recommended that you run a gas stablizer all the time (any suitable for 2 cycle motors) to help prevent phase separation and accumulation of water in the gas which can occur in as little as a week.

The recommended plug for this is NGK's BP8H-N-10 gapped at .040"

Don't let someone cross ref to a Champion plug - no good on this particular ignition."