1973 85 hp evinrude

[barefooter1h]

This old motor is driving me nuts!! good comp 120psi all cyl. It is firing. But is only running on 2 cyls. The carbs have been rebuilt and new gaskets, floats, needle and seat. And it seems to be flooding. Any help with this would be greatly app. Thanks.

 

[tashasdaddy]

Re: 1973 85 hp evinrude

have you done a compression check, 100psi + within 10% of each other, is what your'e looking for. also a test spark with a spark tester,($10 auto parts store) you want 1/2" bright blue spark. did you soak the carb, and blow out all orifices, with compressed air. don't know what jets are adjustable of the top of my head, but here are some adjustment if they apply.

http://www.iboats.com/bbboard/bbBoard.cgi?a=viewthread;fid=28;gtid=818798;gpid=818802

 

[barefooter1h]

Re: 1973 85 hp evinrude

Yes they where clean and blown out. There is no adjustment on the carbs.

 

[dsujen]

Re: 1973 85 hp evinrude

sounds like an ignition problem to me. you need to make sure all 3 cylinders are firing. The old fashioned way is to remove the spark plugs from the engine and put them back in the spark plug wires and lay them against the block so the threads of the plug hit metal. Keep away from any fuel source. You need to hold them with insulated pliers or a piece of wood to be safe cause it will give you a shock.Then you have some one crank the engine. If you have to do one at a time. Look to see if the plug is firing. Look to see what color the spark is. Blue is good, orange or yellow might mean a weak coil or power pack. If you do this at night you will be able to see it better. Also, at night, you can run the motor with the plugs in and while running get a spray bottle with just water in it and mist the spark plug wires, coil and or power pack area. If you see lightning bolts it could be causing part of the problem. Sometimes the insulation on these parts gets weak or dry rotted and it fails to insulate properly and causes the plugs to misfire..

 

[ezeke]

Re: 1973 85 hp evinrude

Can you tell which bank of cylinders is not firing? If it is 1 and 3 it may be because of the lack of grounding. There is supposed to be a grounding strap running from the coil rack down to the the cylinder head. Try disconnecting the ground wires and coil wires and cleaning them.

If the problem is with cylinders 1 and 2 or with 3 and 4, It is most likely that you need to rebuild the carburetor again.