1996 200 looper ignition

[Scoot]

Have a 1996 johnson 200 looper, just replaced all 6 pistons. Ran good on hose (20-30 minutes), put boat in water, started to miss 1-2 cylinders. Ran about a mile, stopped to fish, never started again. Only has fire when plugs are out, put them back, 1-2 cyls. will get some weak fire. Plugs out, strong fire on at least 5 cyls. Installed new CDI stator, no luck. Have another used pack and timer base, swapped both out, no change. Flywheel looks good, no loose magnets, sensor magnet for timer base does not appear to have moved. Have removed all heat sensor wires and kill circuit wires from pack, no difference.

Damn thing's driving me crazy! Any suggestions?

 

[HighTrim]

Re: 1996 200 looper ignition

Couple pages of testing you could try here.

"http://www.boatpartstore.com/page35.asp"

 

[Chris1956]

Re: 1996 200 looper ignition

Did you remove the shift assist switch wire? Are the grounds clean? Did you disconnect the sensor wire for the S.L.O.W. feature?

 

[reeldutch]

Re: 1996 200 looper ignition

what do you exactly mean with no fire?

do you mean the cylinder is not contributing?
do you mean you have no spark with the spark plug in? if so how did you test that?

a cylinder lacking power = bad compression
weak/no spark
feul problem

at least 1 of the 3 is out of wack.

why did you rebuild the engine ?

 

[rodbolt]

Re: 1996 200 looper ignition

if it sparks with the plugs out and no spark with plugs installed you need to test the voltage drop on your battery cables.
its a sure sign tghat either the battery,cabling or starter is going south.
the only difference between plugs in and plugs out is cranking RPM.

 

[22ISLANDER]

Re: 1996 200 looper ignition

Did you replace the plug wires ?

If they are original wires, they can breakdown from the inside out, and ground most of your spark before it reaches the plugs. With the plugs out and ungrounded, you will see a strong spark..

Free to look at 'em...you can also test with an ohm meter, any resistance at all will dictate replacing them.

JMHO

 

[Scoot]

Re: 1996 200 looper ignition

A little history: motor was having problems dropping one bank of cylinders, indicating possible SLOW problem, but intermittent. Replaced blocking diode, no luck. Thought maybe top cylinder may be overheating and triggering SLOW, pulled heads to check water jackets, discovered piston #4 had indentions from ring locator pin stamped into it. Tore down, replace all 6 slugs with new Wiseco pistons (the ones with the relocated pin). Fired up and ran great on hose as stated in original post. Started missing on one or two cyls, then would no longer start. Have two extra starters, thought maybe not enough cranking rpm, swapped starters out, even took original apart, cleaned armature, brushes, and lubed, still no difference. Mechanical tach indicates 250 rpm cranking with plugs in. Should be enough to start according to factory service manual. Also installed brand new battery with highest cranking amps available.

Shift assist switch was removed years ago.
Kill wire and temp sensor wires removed while troubleshooting (SLOW system should be disabled if temp sensor unplugged?)
Double checked all grounds.
With plugs installed, spark jumps 7/16" gap on only 1 or two cylinders
With plugs out, jumps same gap on 5 cylinders
Swapped timer base with a used one, no luck, same symptoms
Swapped pack with used one, same as above
Checked all pins in amphenol connectors, no problems there
Brand new CDI stator, ditto

Will check resistance on plug wires and voltage drop on battery cables, maybe I'll get lucky. Also will try swapping flywheel with one from a running motor just to eliminate that. May be another week or so till I can do that, will update then.

Grew up working on OMC stuff, never been stumped like this. Unfortunately I don't have a meter with a DVA adapter to troubleshoot correctly.

I appreciate all the responses to my post, keep 'em coming!

 

[HighTrim]

Re: 1996 200 looper ignition

Disconnect the SLOW and shift assist wires at the power pack. Both of these will cause sparking issues similar to what you mention. Is there now spark? There should be another wire that runs to your power pack from your solenoid which provides voltage while cranking. This wire is not damaged, nicked, corroded, etc... is it?

This page should help with the drop test.

"http://www.boatpartstore.com/page36.asp"

 

[Scoot]

Re: 1996 200 looper ignition

Finally got back to work on the boat.

Wound up not buying a flywheel and the one I was going to try was different. Decided to get back to basics, pulled all coils off block, scraped bosses down to clean aluminum, scraped both sides of ground straps on coils, moved star washer in between boss and ground strap and tightened firmly. Pulled primary leads from coils, cleaned inside of connectors, pinched them a little tighter, cleaned pins on coils, re-installed. Indexed flywheel for all 6 cyls., put timing light on and all were firing at correct time. Put plugs back in, still had strong spark on all 6. Put it on the flusher and ran it a good 30 minutes. Put in water next day, ran fine at 1200 rpm and up, won't idle below that. Have probably put 3-4 hours on it since then, varied speeds to break in new pistons & rings, runs perfect except for the idling problem.

Haven't had time to chase that down, but will probably re calibrate all carb linkages, adjust slow speed needles, and go from there.

In the meantime, I'm way happy it's finally running again...wierdest diagnosis I've ever done, but talked to a local OMC guy who says that particular type ignition system is picky about good ground.

Thanks for all the suggestions! Will update when I figure out the idling issue.

 

[Scoot]

Re: 1996 200 looper ignition

Pulled bottom two carbs, cleaned, and installed carb kits. Helped somewhat. Then it got to where it won't start unless you disconnect the power pack ground wire. Then it will hit only when cranking. Once it fires, put the ground wire back on and it runs great (still a little rough idling, had to adjust idle stop to increase idle speed). Runs great until you let it set a few days, then you have to pull the ground wire to get it to fire again. Same story.

Finally got tired of all that, bought a brand new CDI pack (the one I had been running was a used OMC pack). Put it on yesterday, fired right up. Ran it on flusher, had to back off on idle stop screw to get idle speed back down to normal. Haven't had time to test on the water, as wind was blowing about 40 mph, but sure sounded good on flusher.

 

[Dhadley]

Re: 1996 200 looper ignition

Just an FYI - the idle speed isn't adjusted with the screw in the throttle arm like a crossflow. It'd probably be a good idea to go thru the sync-n-link from scratch. Might save some stumbling on acceleration problems.

 

[Scoot]

Re: 1996 200 looper ignition

Got back to boat a week after installing pack, same old thing. Have to pull power pack ground wire, crank it over and it fires (only as long as you're cranking), put ground wire back on and it starts and runs great. Put in water, still idling rough, otherwise ran perfect.

Put back on trailer, ran through link & sync procedure as detailed in factory service manual, set idle speed properly, still running a little rough. Plan to adjust low speed needles next time I put it in the water.

Having to pull the ground wire to get it to fire initially is really bugging me, though. Any ideas?