Stumped on Starting 8hp Johnson

[SIGlass]

I bought a 1986 2 cycle Johnson 8hp (J8RCDE) cheap. Previous owner said that it was running fine but suddenly died and would not re-start. Here's the facts:

1. New sparkplugs gapped to .030 (CDI system, no points)

2. Compression 80 and 90 psi

3. Blue spark arcs across a 7/16" gap

4. Pulled flywheel and inspected for sheared key. Everything looked good.

5. Tore down carb and soaked overnight in cleaner. Blew out all passages. Installed rebuild kit including float/needle/seat. Adjusted float height.

6. Primer bulb gets firm after a few squeezes.

7. Disconnected hose from fuel pump to carb inlet. Shot out fuel when engine was spun so appears that the fuel pump is working.

8. Sounds like the primer rod is injecting fuel behind carb OK.

9. Confirmed that fuel is getting into crankcase (can smell it in oil/gas dripping from exhaust.

10. From look/smell of plugs they are seeing fuel. Not flooded.


After many many pulls, there has been zero indication of ignition. Not a cough, even using starting fluid.

Any input/suggestions appreciated. Thanks, Steve

 

[racerone]

Orange / blue stripe wire on the top coil ?

 

[jakedaawg]

Sounds like flooded if you can smell gas. Open throttle all the way and pull a few times to clear flood.

There is a sticky at top that may have a "how to start section" for your motor.

 

[boobie]

How old is the fuel ?? Any water in it ??

 

[SIGlass]

Orange / blue stripe wire on the top coil ?

yes sir

 

[oldboat1]

Any indication the engine overheated? You may need a new head gasket (might equalize compression and improve it a bit).

 

[AlTn]

check your link/sync setting and open the throttle as far as possible in neutral while starting

 

[gm280]

Absolutely flooded if you smell gas in the exhaust. Remove the plugs, dry it out and reinstall. Then try it once again without the choke at first to see if it fires.

 

[flyingscott]

See if the primer is leaking and allowing to much gas in the motor. Also check the float level could be set to high.

 

[ronbourd]

One my 8hp 1982, ELRCNR there were sparks on the 2 cylinders but it would run only on one! The timing was not right for one cylinder but ok for the other cylinder. Had to replace the black box! Now running ok

 

[SIGlass]

Absolutely flooded if you smell gas in the exhaust. Remove the plugs, dry it out and reinstall. Then try it once again without the choke at first to see if it fires.

I assumed the gas smell in the exhaust was from multiple attempts to start without any ignition. Also I would think that failure to get any kind of ignition with starting fluid would indicate some other problem. I've got the LU pulled off now and am waiting for a seal kit. Will try again after I get it back together. BTW appears that there is no choke on this carb. No choke plate and the primer rod appears to only operate the primer pump, no linkage to the carb.

 

[SIGlass]

See if the primer is leaking and allowing to much gas in the motor. Also check the float level could be set to high.

I adjusted the new float so that in its closed position, it is level with the carb body. Didn't think about the possibility of fuel getting sucked through the primer pump. Not sure how to test that. Put suction on the discharge of the pump and see if it seals? Any suggestions how to test?

Thanks.

 

[SIGlass]

One my 8hp 1982, ELRCNR there were sparks on the 2 cylinders but it would run only on one! The timing was not right for one cylinder but ok for the other cylinder. Had to replace the black box! Now running ok

Even with only one cylinder getting correct timing, wouldn't you still get a cough or some sign of ignition with starting fluid?

 

[racerone]

Take the primer out of the picture.----Squeeze the supply from the bowl closed with say a small vice grip.----Pull the motor over to get rid of extra fuel if indeed it is flooded.

 

[ronbourd]

SiGlass, for my E8rcnr with the timing way off for one cylinder and the timing ok for the other cylinder, the engine would only run on one ,but the other cylinder would not fired. Maybe the timing is way off for the two cylinders Ronald

 

[SIGlass]

SiGlass, for my E8rcnr with the timing way off for one cylinder and the timing ok for the other cylinder, the engine would only run on one ,but the other cylinder would not fired. Maybe the timing is way off for the two cylinders Ronald

My understanding is that the timing is not adjustable on this motor (CDI ignition) and that as long as the the flywheel is fixed by its woodruff key, the timing is correct. I would like to hear from anybody who can suggest how to confirm timing without running the motor.

 

[racerone]

Mark your flywheel for TDC for both cylinders.------Hook up the timing light and see where it fires.------Your assistant could be spinning it over with a 1/2 drill on the flywheel nut with plugs out.----------Myself I would simply go to, a bin and put on another CDI , no money spent here.

 

[SIGlass]

Mark your flywheel for TDC for both cylinders.------Hook up the timing light and see where it fires.------Your assistant could be spinning it over with a 1/2 drill on the flywheel nut with plugs out.----------Myself I would simply go to, a bin and put on another CDI , no money spent here.

Thanks, I will check to see where it fires. How many degrees BTDC is correct? Couldn't find it in Clymer's. They just say it's not adjustable.

Please clarify what you mean "go to, a bin and put on another CDI". Replacements go for around $90. Doesn't the fact that I am getting very strong spark indicate that the CDI is working?

Thanks for your help

 

[boobie]

It could be firing at the wrong time on the one cylinder even though you have good spark.