1986 evinrude 28hp

[toys merc]

purchased this 28hp evinrude about one year ago and it ran great for hours. Replaced impeller, corrected starter issue (minor), replaced throtle box (oem), cleaned carbs, replaced hoses, and changed plugs (cross ref to NGK). The motor runs super, but once warmed up does not like to idle long in nuetral and just bumped into gear as if trolling. Still runs great when warmed up and moving. Mechanic says for the year of motor it still runs good when open (i agree), but idel has to do with age and at times possible barometric pressure. How about some greatful help and guidance. Thanks

 

[Vic.S]

Re: 1986 evinrude 28hp

The recommended plugs are Champion QL77JC4 or L78V or QL82C

You do not say what NGK plugs you are using

The equivalent of QL77JC4 is BZ7HS-10 it is important that you do not use resistor plugs such as BR7HS-10 The Q and the Z denote inductive suppresion .
R denotes a resistor plug.

The equivalent of L78V, which is a surface gapped plug is BUHW-2

There is no suitable NGK equivalent to QL82C AFAIK

Therefore is you must use NGK plugs use BZ7HS-10 although the unsuppressed B7HS-10 should also be satisfactory if you do not need to use a suppressed plug


Regarding the atmospheric pressure .. are you at high altitude? If so different jets may be required

 

[rolmops]

Re: 1986 evinrude 28hp

First of all,you should stick to the Champion plugs.OMC engines unlike Mercs prefer Champions.
As for age and idle.....Bovine manure(BS). Some tweaking of your link and sinc and some cleaning of your carburetors(maybe even just running a tank with seafoam) should show improvement.
As for bumping into gear,that is a mechanical issue which is solved by tweaking your remote cable adjustment so it is exactly in the middle between forward and reverse.
My '57s purr like kittens.There is absolutely no reason why yours should not.