1974 85 hp evinrude model#85493B questions

Newbee to iboat and engines here:
I have 1974 85 hp evinrude model#85493B:

Gas mixture: 50:1?

lower end recommended oil?

Spark plug recommendation? Gap?

Should I add seafoam as preventive maintaince?

Should I used Carb Cleaner has a preventave maintance?

I was told the compression is very good... Anything else I should do for maintance before I put it in the water?
Thanks in advance!!

Re: 1974 85 hp evinrude model#85493B questions

Gas mixture: 50:1?............................. Yes, that's correct.

Lower end recommended oil?................. The 1974 model has what is called "Shift Assist", meaning that the lower unit incorporates a oil pump. As such, the lower unit demands what is called either "Premium Blend" or "Type C" gearcase lube, designed especially for the units that incorporate a oil pump (Electric Shift & Shift Assist). The container will specify that it is for the "Electric Shift" model (Actually printed on container). DO NOT use "HIVis 80/90w" which is for the standard mechanical shift models.

Spark plug recommendation? Gap? ........ Champion QL77JC4, gapped at either .040 (Orig Recom) or .030 (Revised Recom 1990s).

Should I add seafoam as preventative maintenance? ........ Another member will answer that.

Should I use Carb Cleaner has preventative maintenance?........ No, a waste of time. If a carb problem, dismantle and clean etc.

Oh, having someone tell you that the compression is good compares with thinking about buying a bridge. Compression gauges are fairly cheap (Wal*Mart, K-Mart, many stores). Buy one, keep it on hand and check it yourself.

Re: 1974 85 hp evinrude model#85493B questions

Thank you

Re: 1974 85 hp evinrude model#85493B questions

jdaziel said:

Thank you

Click to expand...

Just wondering what would be the proper prop for this outboad when put an old 1970's silverline 15' fibergalss-rated for 5 passengers max.

Presently have a 13-1/4 X 17.

The motor will not rev beyond about 4,000rpm in the water, and about 27-28 MPH. New, properly gapped spark plugs, and the carb opens fully. Compression on all cylinders is 103-110, and all cylinders get spark.

Any ideas?