Johnson 225 once warm low power

[Taylor9988]

1996 johnson 225 looses power after running around the lake for 30 mins. Once the motor is warm and I shut down and start back up after fishing for 30 mins WOT it will not rev all the way out and won't even get my 20ft stratos on plane. Any ideas?

 

[Joe Reeves]

Two thoughts that might cause that problem:

1 - The stator under the flywheel is the beginning of the ignition and battery charging system... the two large black coils at the rear of the stator provide the AC voltage to the powerpack capacitor, needed in order to engage the ignition/spark. This is actually the hottest portion of the engine. In time (a lot of time), that 35amp stator will start to enter a meltdown scenario.... there will be a sticky looking substance dripping down on the powerhead from those rear mounted black coils.... and this results in a AC voltage drop to the powerpack, which in turn results in weak, erratic, and eventually no ignition.

When cold, a stator that has just started to fail recently may function just fine... but when hot may result in faulty ignition. After running, you shut the engine down, all the water drains out of the engine, the combined heat of the engine rises to the top portion, to the stator area, and just sits there cooking, getting hotter and hotter..... something you want to take a good look at.

2 - The shift cutout switch, located on the shift linkage just as it enters the engine's nylon bushing may be sticking. This switch linkage may be free enough to function when cool, but when hot and coupled with any possible salt corrosion, could stick which would knock out the ignition to the starboard bank of cylinders. Easy enough to check/test... simply disconnect it momentarily.

Question: If you let the engine cool down, close to the original engine temperature... considered a cold engine... does the engine run normally once again? If so, that does bring into fact the heat mention.

 

[Taylor9988]

Two thoughts that might cause that problem:

1 - The stator under the flywheel is the beginning of the ignition and battery charging system... the two large black coils at the rear of the stator provide the AC voltage to the powerpack capacitor, needed in order to engage the ignition/spark. This is actually the hottest portion of the engine. In time (a lot of time), that 35amp stator will start to enter a meltdown scenario.... there will be a sticky looking substance dripping down on the powerhead from those rear mounted black coils.... and this results in a AC voltage drop to the powerpack, which in turn results in weak, erratic, and eventually no ignition.

When cold, a stator that has just started to fail recently may function just fine... but when hot may result in faulty ignition. After running, you shut the engine down, all the water drains out of the engine, the combined heat of the engine rises to the top portion, to the stator area, and just sits there cooking, getting hotter and hotter..... something you want to take a good look at.

2 - The shift cutout switch, located on the shift linkage just as it enters the engine's nylon bushing may be sticking. This switch linkage may be free enough to function when cool, but when hot and coupled with any possible salt corrosion, could stick which would knock out the ignition to the starboard bank of cylinders. Easy enough to check/test... simply disconnect it momentarily.

Question: If you let the engine cool down, close to the original engine temperature... considered a cold engine... does the engine run normally once again? If so, that does bring into fact the heat mention.

Thanks for the quick reply! The previous owner installed a new flywheel, stator, and power pack. I went out and found a lot of "glue" drippings from the stator but its new... When I was on the lake I pulled the wires to the temp sensors and shift interrupter switch to eliminate slow and the shift interrupter switch from the equation. What could cause the new stator to suffer a melt down? A bad rectifier?

 

[Joe Reeves]

Thanks for the quick reply! The previous owner installed a new flywheel, stator, and power pack. I went out and found a lot of "glue" drippings from the stator but its new... When I was on the lake I pulled the wires to the temp sensors and shift interrupter switch to eliminate slow and the shift interrupter switch from the equation. What could cause the new stator to suffer a melt down? A bad rectifier?

Normally, if a water cooled voltage regulator/rectifier assembly is faulty, that will cause the tachometer to become erratic, false reading, not work at all, etc. If your tachometer has been acting up, as mentioned, that's a dead giveaway that the regulator//rectifier assembly has failed and requires replacing. If you're absolutely sure that the new stator is melting down and that the drippings are not from the old failed stator.... then yeah, suspect the previous owner was cutting corners, hopefully accidentally. The following is from my database.

(Testing Tachometer With Water Cooled Regulator/Rectifier)
(J. Reeves)

A quick check is to simply plug in a another new tachometer as a piece of test equipment. If the new tach works properly and the old tach didn't, obviously the old tach is faulty.... but usually boaters don't carry around a spare tach (see below).

A faulty rectifier wouldn't damage the tachometer, the tachometer simply wouldn't work. This is due to the fact that the tachometer operates off of the charging system and the rectifier converts AC voltage to DC voltage, enabling the charging system. A faulty rectifier disables the charging system, and the tachometer simply doesn't register.

However.... those water cooled regulator/rectifiers that are used on the 35 ampere charging systems (and some others) bring into play a different type problem, and as you've probably found out, they are really a pain to troubleshoot via the proper procedure. There's an easier way.

The tachometer sending/receiving setup operates off of the gray wire at the tachometer. That same gray wire exists at the engine wiring harness which is connected to the engine electrical terminal strip. You'll see that there is a gray wire leading from the regulator/rectifier to that terminal strip, and that there is another gray wire attached to it. That other gray wire is the wire leading to the tachometer which is the one you're looking for.

NOTE: For the later models that DO NOT incorporate a wiring terminal strip, splicing into the "Yellow Wire" mentioned will be necessary.

Normally the Gray wire leading from the tachometer is attached at the terminal strip to another Gray wire which leads from the water cooled voltage regulator/rectifier...... remove the gray wire that leads to the tachometer. Now, find the two (2) yellow wires leading from the stator to that terminal strip. Hopefully one of them is either yellow/gray or is connected to a yellow/gray wire at the terminal strip. If so, connect the gray wire you removed previously to that yellow/gray terminal. Start the engine and check the tachometers operation, and if the tachometer operates as it should, then the regulator/rectifier is faulty and will require replacing. If the tachometer is still faulty, replace the tachometer.

If neither of the yellow wires from the stator is yellow/gray, and neither is attached to a yellow/gray wire, then attach that gray tachometer wire to either yellow stator wire, then the other yellow wire, checking the tachometer operation on both connections.

I've found this method to be a quick and efficient way of finding out which component is faulty.... the tachometer or the regulator/rectifier. It sounds drawn out but really only takes a very short time to run through. If the water cooled regulator/rectifier proves to be faulty, don't put off replacing it as they have been known to catch on fire with disastrous consequences.

 

[Taylor9988]

Normally, if a water cooled voltage regulator/rectifier assembly is faulty, that will cause the tachometer to become erratic, false reading, not work at all, etc. If your tachometer has been acting up, as mentioned, that's a dead giveaway that the regulator//rectifier assembly has failed and requires replacing. If you're absolutely sure that the new stator is melting down and that the drippings are not from the old failed stator.... then yeah, suspect the previous owner was cutting corners, hopefully accidentally. The following is from my database.

(Testing Tachometer With Water Cooled Regulator/Rectifier)
(J. Reeves)

A quick check is to simply plug in a another new tachometer as a piece of test equipment. If the new tach works properly and the old tach didn't, obviously the old tach is faulty.... but usually boaters don't carry around a spare tach (see below).

A faulty rectifier wouldn't damage the tachometer, the tachometer simply wouldn't work. This is due to the fact that the tachometer operates off of the charging system and the rectifier converts AC voltage to DC voltage, enabling the charging system. A faulty rectifier disables the charging system, and the tachometer simply doesn't register.

However.... those water cooled regulator/rectifiers that are used on the 35 ampere charging systems (and some others) bring into play a different type problem, and as you've probably found out, they are really a pain to troubleshoot via the proper procedure. There's an easier way.

The tachometer sending/receiving setup operates off of the gray wire at the tachometer. That same gray wire exists at the engine wiring harness which is connected to the engine electrical terminal strip. You'll see that there is a gray wire leading from the regulator/rectifier to that terminal strip, and that there is another gray wire attached to it. That other gray wire is the wire leading to the tachometer which is the one you're looking for.

NOTE: For the later models that DO NOT incorporate a wiring terminal strip, splicing into the "Yellow Wire" mentioned will be necessary.

Normally the Gray wire leading from the tachometer is attached at the terminal strip to another Gray wire which leads from the water cooled voltage regulator/rectifier...... remove the gray wire that leads to the tachometer. Now, find the two (2) yellow wires leading from the stator to that terminal strip. Hopefully one of them is either yellow/gray or is connected to a yellow/gray wire at the terminal strip. If so, connect the gray wire you removed previously to that yellow/gray terminal. Start the engine and check the tachometers operation, and if the tachometer operates as it should, then the regulator/rectifier is faulty and will require replacing. If the tachometer is still faulty, replace the tachometer.

If neither of the yellow wires from the stator is yellow/gray, and neither is attached to a yellow/gray wire, then attach that gray tachometer wire to either yellow stator wire, then the other yellow wire, checking the tachometer operation on both connections.

I've found this method to be a quick and efficient way of finding out which component is faulty.... the tachometer or the regulator/rectifier. It sounds drawn out but really only takes a very short time to run through. If the water cooled regulator/rectifier proves to be faulty, don't put off replacing it as they have been known to catch on fire with disastrous consequences.

I'm not a 100% sure the new one is melting down however, I do not have a tach. I have one on order now. So for sure the stator is bad, causing the low power issue? But we are not sure if the reg/rectifier is bad due to no tach? Should I just replace both the stator and reg/rectifier to prevent further damage to other electrical components? Do you happen to have any laying around?

 

[Joe Reeves]

No, I'm not saying that either the stator nor the reg/rec is bad.... I'm saying it is a possibility.

Pertaining to the stator.... You would need to look up whatever the readings are on the stator to check it with a meter, and also visually inspect it to see if it is actually encountering a meltdown.

The regulator/rectifier assy can be tested via using the tachometer, once installed, as a test meter as I previously mention.

Don't forget to disconnect the shift interrupter switch momentarily to see if that cures the problem.

 

[Taylor9988]

I'll give it a test once the tach arrives! When I was on the lake and it was acting up I pulled the temp switches and the shift interrupter switch wires and no difference. So I'm sure it has to do with the ignition system. Thanks for the responses.