1999 Johnson 200, erratic RPM

M

Mod2

Senior Chief Petty Officer
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Jun 19, 2003
Messages
713
Re: 1999 Johnson 200, erratic RPM

mmcpeck...well I will be dipped....can't read the original post...thought ya' said Rude not Johnny.....Old Timers Diesease strikes agin.<br /><br />Under the flywheel is a timer base. Since ya' changed out power packs with a known good one, this is the next place to look.<br /><br />There should be six leads from the timer base to the pack. Don't know right off hand which wire is which. But if the timing coil in the timer base for the cylinder in question is going south, then that's the bad guy. If you have a wiring diagram, find the trigger wire for the bad cylinder. With the engine cranking, you should get at least 2.5 volts or better from the trigger wire. Anything less is not good. One thing for sure, don't go runnin' the engine like this to long or you may trash a cylinder.
 
C

Cricket Too

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May 14, 2003
Messages
1,732
Re: 1999 Johnson 200, erratic RPM

Mod2....Yeah i think you're right, I'm pretty much at the end of my rope. I have not been out on it for 2 weeks because of this and it is killing me, so I guess I will suck it up and take it to the dealer. Thanks.
 
D

DJ

Guest
Re: 1999 Johnson 200, erratic RPM

mm,<br /><br />I think this is one for Dhadley or Joe Reeves. <br /><br /> Sorry! :(
 
O

ob

Admiral
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Aug 16, 2002
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6,992
Re: 1999 Johnson 200, erratic RPM

I think mod2 is onto something with the timing coil for the cylinder in question.
 
C

Cricket Too

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Re: 1999 Johnson 200, erratic RPM

Mod2....Thanks for that advice about the timer base, someone else actually told me about that but I had no idea of how to go about checking it. Can I get the wiring diagram through this site or from just any manual? Thanks again, I really appreciate it. Thanks also ob.
 
P

P.V.

Chief Petty Officer
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Mar 14, 2002
Messages
452
Re: 1999 Johnson 200, erratic RPM

Yes, it sounds like you are getting close. First, you must have a factory manual. If you have an aftermarket one, throw it away!!! Next you need a digital ohm meter to read sensor and charge coil resistance. And then yo will need a peak reading voltmeter to read a/c voltage out of the sensors and charge coils. It gets real tight where the power pak leads ar but you can get additional leads from the vendors listed in the FACTORY MANUAL . Stevens Instrument and MercTronic, etc...
 
C

Cricket Too

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Re: 1999 Johnson 200, erratic RPM

By the way guys, how hard is it to replace that timing coil if it does turn out to be the culprit? Do I need to pull the flywheel? Thanks.
 
C

Cricket Too

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Messages
1,732
Re: 1999 Johnson 200, erratic RPM

P.V....Thanks for the input. Yeah I know how tight it gets in there, I found out when swithching the power packs. What do you mean by a peak reading voltmeter, just a regular digital voltmter or multimeter? Also when you say additional leads do you mean lead extenders that make it easier to work with? Where can I get a Factory Manual, from any dealer? Thanks for the help.
 
S

sparkroost

Petty Officer 1st Class
Joined
Mar 23, 2003
Messages
312
Re: 1999 Johnson 200, erratic RPM

I had the same problem with my motor. There was a broken wire where it is clamped to the timer base. When at idle, the wires were in such a way that it made contact. As the timerbase moved the wire opened up and closed. I took off the timerbase, put ohm meter on each individual sensor and shook wires to find it and any possible others. Soldered wires together and put heat shrink tube over it.<br /><br />Just a thought
 
Joe Reeves

Joe Reeves

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Feb 24, 2002
Messages
13,262
Re: 1999 Johnson 200, erratic RPM

Mmcpeck.... I've hesitated to get involved in this problem due to the fact that I retired quite a few years before its existence (the engine) came about. However......<br /><br />The magnet scenario pertains to the outer magnets, not the inner magnets which control the timing. Having the outer magnets come loose or breaking will affect the charging capabilities, and will also have an effect on the AC power being applied to the powerpack(s). Bottom line here is to check the magnets to make sure they are attached in their proper location.<br /><br />You mentioned that you thought that having a faulty sensor would affect more than one cylinder. This is incorrect as there would be six (6) sensors, one (1) sensor for each cylinder. Hopefully you have a service manual (if not, get one) which would state how to check each sensor and the timer base in general with a ohm meter. This area would be where I would be looking.<br /><br />Here, I'm assuming that this engine is a standard 200hp Loop Charged engine. Are you using the same spark plugs in both engines? If so, are they Champion QL77JC4 plugs? The book states (if I'm not mistaken) that they should be gapped at .030 . For many years, the gap setting was .040 . If it were I and all else checked out okay, including the sensors, I' try setting them at .040 just to see if that made a difference.<br /><br />Keep us informed.
 
C

Cricket Too

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Messages
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Re: 1999 Johnson 200, erratic RPM

Thanks, Joe, sparkroost, P.V., Mod2 and all. I am deffinetely gonna look at that timer base and then take it from there, I really appreciate the advice and direction from all. <br /><br />BTW Joe.....The plugs I have in both motors are Champion QL78YC, that is what the dealer said was in the book from the manufacturer. If it is wrong please let me know and I will change them all. Thanks again and I'll keep you posted on my test of the timer base.
 
B

Bluefish

Petty Officer 2nd Class
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Mar 14, 2001
Messages
125
Re: 1999 Johnson 200, erratic RPM

Bump have you fond the problem ?
 
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