9.9 Johnson High Speed Miss

[wrmdunker]

I have a 9.9 Johnson Model 1077ELA. It?s a 1977, long shaft, electric start. It?s new to me last October and we only ran it in a barrel before we bought it. Came with the 1652 Monark jon boat. PO seemed very forthright about all things. He did say he had it serviced recently, spent $300, but couldn?t produce an invoice or give details about what was done other that new gear oil??. That?s all the history I have. Motor looks great though and very clean. Must have been stored inside. Even the cowling gasket is still soft and flexible.

OEM metal gas tank. Siphoned out the ? gallon the PO gave us and had a little sediment. Switched to one of my good metal tanks. Got the OEM manual off eBay over the winter. Put it in storage garage. Ohio winters......

This week, I changed plugs. PO had NGK and I switched to Champion QL77JC4. Compression was 95 psi on both cylinders. Ran a gallon of fresh gas with 8 ounces of Seafoam. Started and ran great. Good water stream. Very little smoke. So much for the history.

Ran the boat on a small lake with a 10 hp limit and ran good but I didn?t push it to WOT. Turned it over to my son to drive (it?s his rig) and soon after he trottled up it had a misfire about every 3 to 4 seconds. When he slowed down, it semed fine. I took over and gradually increased speed and ran fine again he he swears I was going as fast or fasted. Still never went WOT.

Only difference I see is that he may have been more aggressive with the throttle than me. Any thoughts?

WD

 

[the machinist]

Re: 9.9 Johnson High Speed Miss

How does it start?

A guess would be maybe you need to check the sync/link. That is check to see if the carb arm is in the right location (mark) on the timing plate at an idle just when you start to advance the throttle. You may have this adjustment off enough to where your high speed timing is off.

Check this website out as it may help http://www.sschapterpsa.com/ramblings/Johnson 9.9_15.htm

 

[wrmdunker]

Re: 9.9 Johnson High Speed Miss

Starts great. fired right up with very little choke. It is an electric start. I am familiar with LeeRoys Ramblings. Helped me to rebuild a fuel pump last year. Great site.

I know about sync/link but have never done one.

BTW, the manual only talks about plug issues like cracked insulators or not torqued right. Any thoughts that this could be a dirty carb?

 

[boobie]

Re: 9.9 Johnson High Speed Miss

Sounds like you've got a high speed ignition miss. Pull one plug wire at a time and see if you can narrow it down to a cyl when it's acting up.

 

[wrmdunker]

Re: 9.9 Johnson High Speed Miss

The machinist and LeeRoy are one in the same.........You are a godsend to the DYI community on the 9.9s and 15 hp.

I did the sync/link. It was off a bit. With the mark lined up on the cam roller I was not touching by about .008 inch. Alternately, when the cam did touch the roller, here is a photo of where the mark was located.


As an FYI to all who may read this in the future, the alligator clip and wire worked great. Just dont make the wire too long or is adds weight to the throttle shaft and opens it slightly. 3 inches seems all that is necessary.

I hope this helps. Will try the plug disconnent as well, boobie.

 

[wrmdunker]

Re: 9.9 Johnson High Speed Miss

A couple of other items while I was in there.........

Is this a choke solenoid? I don't have that feature on my remote controls so I wonder if there is any harm in removing. I'ts just in the way. I replaced the fuel line from the pump to the carb since it was cracked. Again, solenoid in the way. Looks like a plug connector.

Lastly, I pulled the slow speed needle screw and the tip sure looks a bit bent to me. Is this bad enough to replace? Only had the motor out once and slow speed seemed fine. I played with the adjustemnt knob the one full turn and did not see a change in performance. Perhaps this is why. BTW, the screw was out 1 1/4 turns.

Any thoughts?

 

[wrmdunker]

Re: 9.9 Johnson High Speed Miss

For those who might look at this in the future......

The motor was not missing, it was jumping out of gear which made the unit jump and produce a loud sound. Found that the cable needed adjustment at the control arm. Now shifts solid and stays in gear. Happily I did not see metal in the lower unit oil so I don't think we damaged any gears.

Very happy with this motor.