Johnson 6 hp won't start

[creeksidelc]

I checked the compression again today and it's actually up to 75 on both cylinders, I've got a spark that jumps over 1/4 inch, points are set to .2 still motor will do absolutely nothing even with starting fluid. When I took off the carb and look behind it there is a metal plate with 2 holes and on the other side of the holes there is something brown that looks like gasket material. So there isn't a clear open channel for the gas to go from thencarb to the cylinders. Is this normal and those brown gaskets and a check valve or is something wrong here?

 

[oldboat1]

May be a typo, but point setting should be .020. I'm not sure, but think you are describing the throttle plate in the carb -- not sure what the brown stuff is, and might try some carb cleaner on it. Other than that, the throttle plate would be normal -- that's the part that opens with the throttle (pushed open by the cam follower).

 

[oldboat1]

After you rebuilt the carbs, did you reset the idle needle up at the top? Initial setting is 1 to 1 1/2 turns open (counterclockwise) from seated. Should start and run with that setting. Adjust from there (slightly leaner, clockwise, until the engine backfires or stalls, then c.clockwise about 1/4 turn.) The holes in the throttle plate must be open so air and fuel can be drawn through. Maybe a prior owner tried to block them for some reason.

 

[Bonaventure]

Did you change the Spark Plug Wires? Inspect the Magnetos to see if they are cracked anywhere - look for any flaws. There are instruction on the web to show how to test a magneto with a Multi-meter, in fact I suspect you can find this in iboats. Changing the wires is an inexpensive step.

 

[racerone]

The reed valves are a " brown " material.----Actually a copper alloy of some sort.-----They are a check valve.-----They open when piston goes up in the cylinder to let air / fuel into the crankcase.----You might want to look on u-tube ---for a tutorial ---on how a 2 stroke engine works.----That will help in your trouble shooting.

 

[Bluestream]

Wrong plugs, worn reeds, reset idle needle? All are irreverent to getting that engine to fire. All it needs are these three things: Compression, spark and fuel. If any one of these are missing, you are dead in the water. Can you confirm the coils have no cracks?

 

[racerone]

A 2 stroke needs a fourth elusive item ----That is crankcase compression.---That moves the fresh fuel charge into the cylinder.

 

[creeksidelc]

Coils are brand new and no cracks. Idle adjustment is set at 1.5 turns out. Plug wires are good and spark is good. What I was describing in my last post was the reed valves. They don't seem to be letting any air backnout as I still have good compression. I don't understand it. Motor has good compression, good spark, air and fuel. But yet does nothing. Is there anything internal that could be wrong but yet the motor would still have good compression?

 

[racerone]

Sorry, ---The reed valves have nothing to do with compression in the cylinder !!

 

[oldboat1]

It seems to me squirting ether into the cylinders would get you a pop with any kind of compression -- maybe none -- and decent spark. If you have 1/4 to 3/8 spark measured with a tester at the leads, maybe the plugs are the problem. Spark issues in old motors are overwhelmingly related to magneto issues, but could also be bad or poorly gapped plugs. The other common problem is the spring clip in the boot, but if you are seeing spark with an inline tester, the spring clip appears to be properly connected. (The connector's spike has to pierce the 7mm plug wire, contacting the wire core. Automotive wiring will not work.)

If it were me, I would get a fresh set of J4C plugs and try them. At a minimum, use some sandpaper to clean the contacts on the plugs you have, and gap them to .030 with a plug gap gauge.