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1998 Johnson 200 J200TXECM exhaust popping and engine shake

bgodden

New member
I'm in need of a little advice please.

I have a new tank, new pick up, new fuel line from tank to carbs including newfilters and primer ball.

History:

Installed new tank, filters and lines, had motor compression tested andserviced. I’m running all new fuel and oil.

I rebuilt he carbs, and verified the floats are adjusted properly.


The motor still pops about every 10-30 seconds from theexhaust and runs with a slight vibration. When the exhaust pops, the RPMs lowerslightly and the motor picks back up. The engine’s RPMs seem to be a littlehigher than normal.
The motor did this on our first trial, then I found afrozen needle and seat which did not allow any fuel into that carb, so I replacedthat needle and seat and the motor ran great for about a mile, then started todo the same thing, so I rebuilt all carbs to no avail.
I am getting spark from every coil and the plugs are new.
I just noticed that my onboard amp meter is showing 12volts while the engine is running. I know an automotive alternator puts outabout 14 volts, and would assume the stator should do the same. I’m not sure ifthis could be related, if possibly the stator is not supplying the power packwith enough juice. And I’m not sure how to test it to determine its function.
I also just noticed my primer solenoid is no longerworking, possibly frozen partially open? There is no response from it when I pushin the key, and no consistent response when I manually turn the red valve.Turning the manual valve does effect the motor, causing to run less consistent.

I have read that the exhaust pop is either poor ignition,or running too lean. Again, all new gaskets in the carbs, and carb to manifoldgaskets are new.
The motor sat for several years prior to me obtaining it.

Thank you for any insight.



 
Sorry if this doesn't help but..
I have the same problem. I've been told the gas has too much oil, I opened gas tank and it's a dark brown color (obviously too much oil)
I went and got new gas and did 50-1 I'll be testing it out tonight and let you know the results.
 
Sorry if this doesn't help but..
I have the same problem. I've been told the gas has too much oil, I opened gas tank and it's a dark brown color (obviously too much oil)
I went and got new gas and did 50-1 I'll be testing it out tonight and let you know the results.

Thank you. I plan to replace the primer solenoid tomorrow as well. I will keep posting.
 
Well it seems to have worked. I submerged it in a container of water and took off the flush muffs. I don't hear it anymore. So it might have worked or might just be muffled by the container of water. Haha. Setting up the gauges later to check rpm.
Will post later.
 
Well it seems to have worked. I submerged it in a container of water and took off the flush muffs. I don't hear it anymore. So it might have worked or might just be muffled by the container of water. Haha. Setting up the gauges later to check rpm.
Will post later.

This motor ran as it should, with no poppin, in the past, using the muffs. I'm sure the popping would disipate if I submerged it, but there would still be a problem.
 
Ok. So I installed a new primer solenoid, the motor seems to be working great now, except for the charging/tach issue now. I have to test the stator and rectifier to see if they are working. I'm not getting any tach reading and the batteries are at 12.5 volts while running, when they should be around 14.5, or so I've read.

Now after idling for about 10 minutes, the motor starts to die, I squeeze the primer ball and thee motor's health returns. Possible fuel pump? But I also noticed there are 2 wires going to the VRO pump from the Rectifier. Could a bad Rectifier cause the fuel loss?
 
The VRO pump is not an electric pump and it has nothing to do with battery voltage or the rectifier.


Thank you.

As the motor heated up the same issues reoccured. The motor started to pop through the exhaust. Then the motor started to die, so I pumped up the primer ball and the motor started to run normal again (with the popping of course). This happens with the onboard tank, and with an external tank. I thought it would be the fuel pump so I disassembled it to find nothing wrong, put it back together and the motor no longer stalls. I'm baffled. I still need to test the stator and rectifier, as I am only getting 12 volts at the battery while running and no tach readings.

I'm GUESSING the stator could be intermittently failing causing the exhaust pop. Maybe? Could a bad rectifier do the same? Or is a bad stator not feeding the rectifier the required voltage? I need a drink!

Again, when the the exhaust pops, the RPMs drop a little as if it was missing.
 
Thank you.

As the motor heated up the same issues reoccured. The motor started to pop through the exhaust. Then the motor started to die, so I pumped up the primer ball and the motor started to run normal again (with the popping of course). This happens with the onboard tank, and with an external tank. I thought it would be the fuel pump so I disassembled it to find nothing wrong, put it back together and the motor no longer stalls. I'm baffled. I still need to test the stator and rectifier, as I am only getting 12 volts at the battery while running and no tach readings.

I'm GUESSING the stator could be intermittently failing causing the exhaust pop. Maybe? Could a bad rectifier do the same? Or is a bad stator not feeding the rectifier the required voltage? I need a drink!

Again, when the the exhaust pops, the RPMs drop a little as if it was missing.


Motor is working great now after new stator, rectifier, power pack, carb rebuild, second set of plugs, and the primer solenoid.
 
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