1971 Evinrude Starflight 85HP Misfire

[geoffreymoreland@gmail.com]

Hello all, I am new to boating and the forum.

I have recently purchased a 1971 MFG Sprint 170 with a 1971 Evinrude 85 HP Starflight (85193)

the motor ran well on the first outing on the lake. However, recently the motor has had a severe misfire at idle, and in gear. On occasion the motor misfires while at half to WOT. It really only shows itself after the engine has run for 20 minutes or so.

Things I have repaired/replaced:

New fuel pump
New spark plugs
Carb clean (they were extremely clean)
Idle screw adjustment.
Re-wired the CDI power pack (the wires were all cracked and exposed, touching)

Note:
I have a new coil pack and rectifier on order.
I only run no ethanol fuel.
I run 50:1 Penzoil Marine 2 stroke oil.


As a side note: after repairing the CDI box and replacing the plugs and pump, the engine completely cut out twice while at wide open throttle. The only way to even get any power to the motor after trying to restart was to disconnect the battery and “reset” whatever was causing the issue.

** I also have the Factory Service Manual.

Thank you!

 

[F_R]

So you haven't removed the flywheel and serviced the breaker points and anti-reverse cut-out ring? That is one of the first places I'd have gone. Well besides the rotten wires on the amplifier anyway.

 

[racerone]

+++^ ----Remove that flywheel.-----No such thing as anything " resetting " when you disconnect the battery !!

 

[geoffreymoreland@gmail.com]

Thank you all. I will remove the flywheel this week and report back. Now just to find the nut size..

 

[racerone]

that be 1-5/16"-----And the puller screws are 5/16 fine thread

 

[F_R]

Deleted

 

[geoffreymoreland@gmail.com]

Thank you. Ironically I’m picking up another Starflight 85HP tonight from down the street. $200. It’s a 1974 and I think they changed some of the ignition components between 71 and 74. Good for a spare parts motor.

 

[racerone]

Well-----I think you will find that these 2 motors do not have very much in common.-----These 2 motors are totally different not good for spare parts at all !!!

 

[geoffreymoreland@gmail.com]

Looking closer I’ve noticed that. I suppose it will be a “spare outboard” then.

 

[geoffreymoreland@gmail.com]

I inspected the points today. The one point was right at a perfect .010, however, the other was wayy under .010. Makes me think as the engine warms up and expands the metal the point can’t break the gap anymore. I did Howe’s order a new ignition module and coil pack. The old one was quite damaged. I will test run her when all the new parts are on. Is my theory correct? Thanks again.

One grateful Vet!