Getting close! Just need a little more help.

[george3405]

Okay, I figured out, I think, I have found the problem with my 1989 48 SPL Evinrude engine. It has been backfiring and not starting. When I went to replace the ignition module the boat was broken down on the beach. Someone told me to stuff the cylinder with rope to lock up the engine so I could remove the flywheel nut. Later when I wnet to remove the rope it was stuck. I turned the engine with a pry bar on the flywheel and the engine finally moved and the rope came out. What i think happened is that a small piece of the rope got stuck in the exhaust valve. The top cylinder has a compression reading of 120 lbs. and the bottom cylinder is 150 lbs. My question is how do I get to the exhaust valve, which I'm assuming is a reed valve. My service book does not give much detailed info. Any help is appreciated.
George3405

 

[F_R]

Re: Getting close! Just need a little more help.

It doesn't have exhaust valves. It does have intake reed valves, but they are way on the front side of the crankcase and do not affect compression in any way.

 

[tashasdaddy]

Re: Getting close! Just need a little more help.

maybe time to pull the head and see what happening.

 

[steelespike]

Re: Getting close! Just need a little more help.

Did the rope come out with no damage/cuts etc.?
There are exhaust ports in the cylindersthere is a slim chance some rope got stuck in a port and was cut off by the piston.Not likely the rope is plugging the ports probably 2 or 3 ports in each cylinder.There is a chance if you pull the plugs and peek in with a lite you maybe able to see the ports.If you look in the front of your manual there may be a drawing of a 2 stroke engine demonstrating the 2 stroke operation.You will be able to observe the ports that the piston covers and uncovers in the course of operation.Maybe when forced it by the nut you damaged the ignition cam or the flywheel.
Didn't you say the flywheel damaged the coil and wires ? You may have damaged the carb,spark sync if so equipped.
If you are getting backfire the timing is out or plug wires are on wrong.

 

[george3405]

Re: Getting close! Just need a little more help.

I tried switching around the plug wires and still got the same backfire. How can I check the timing without the engine running? When the accelerator is advanced the linkage advances the timing. However, the linkage has not been changed since it ran the last time. Now I am confused.
George3405