225 Johnson surges after warmup

" I have a 1987 Johnson 225 th

" I have a 1987 Johnson 225 that runs perfect after I first start it up but after I have run the river channel(about 5 miles) at about 30 knots the engine starts to surge,i.e. it drops about 3,000 rpm for a moment, then kicks back up to where it was and seems to repeat this behavior for the rest of the day. I have recently replaced the stator coil and the flywheel magnets and sparkplugs and wires. Any ideas? "

check anti-siphon valve at fu

check anti-siphon valve at fuel tank check fuel pumps check pick-up tube in fuel tank check electronic control unit may be getting a false reading like high temp. no oil over rev. ect. good luck. norm let me know what you find out.

"Mike.... You say "the eng

"Mike.... You say "the engine starts to surge,i.e. it drops about 3,000 rpm for a moment, then kicks back up to where it was and seems to repeat this behavior for the rest of the day. I have recently replaced the stator coil and the flywheel magnets and sparkplugs and wires."

A surge is a rather slow type drop in rpms such as one might have if a fuel problem (restriction or air leak) was encountered. The engine would slow down as fuel diminished, then due to low rpms, the fuel supply at the carbs might increase and the rpms would rise again.... and the process would repeat over and over.

However, the items you've replaced pertain to a possible ignition problem. If a intermitent ignition problem is what you're encountering, the problem would be a ignition breakup.... the rpms would drop suddenly (not a slow gradual drop), and would (if ever) cut back in just as suddenly (a instantaneous power loss and recovery). This is usually explained to a mechanic as "Hey, my engine's cutting in and out"<grin>

Which problem do you have?

If ignition, your s/plugs should be Champion plugs QL77JC4 with a gap of .040. You could have a faulty ground wire at the powerpack(s), or a ignition switch starting to short out. The switch can be tested by simply removing the "black/yellow" wire from it (this eliminates the shut down (short out) circuit from the p/pack(s). Note that with this wire removed, you can not shut the engine off via the ignition switch. If you can't get at the back of the ignition switch, simply remove the "black/yellow" wire at the pack(s) by unpluging them.

Also, check the shift assist cutout switch which is located at the shift linkage arm at the bottom of the powerhead just to the rear of the carburetor area (follow the shift cable backwards). You'll also see a "black/yellow" wire that runs from that switch to the powerpack. The purpose of the switch is to momentarily eliminate the ignition of one bank when shifting (so fast you don't notice it when it's proper). If that switch is acting up, it would affect the ignition. To check that, simply follow the "black/yellow" wire to a point where you see a rubber plug in type connector... and unplug it.

All coils should have continuity from the s/plug rubber boot spring connector to ground, and from that same spring connector to the small primary lead of the coil.

Let us know what you find.

Joe "

" I finally got a chance to do

" I finally got a chance to do some troubleshooting and checked power pack ground connection and all the coil ground connections as suggested by Joe. Now, however, the engine will not even start. It will fire like its going to start but will not even run for a second. I disconnected the shift interrupter switch and the key cutoff wire as suggested but it still will not start. Is this a typical failure mode for the power pack, or stator coil, or timer coil? How can i test these components? The fuel is fresh and engine fires and I can see fuel being pulled into carbs so I don't think its a fuel issue. "

"Mike.... I've re-read all

"Mike.... I've re-read all the data here and you've covered just about everything except the powerpack. However before replacing that $$$ item, I'd suggest going back to basics first by checking the compression first, then with all the s/plugs still removed, rig up a spark checker whereas you can set the gap(s) to 7/16", then with the ignition key in the ON position, crank the engine over. If the spark is a strong blue flame and jumps all six (6) gaps, the ignition is not the problem.

If you have no spark and/or weak erratic spark, disconnect the large red main connector at the engine thustly eliminating the instrument cable and all assorted items. Now, using a jumper from the battery side of the solenoid to the small terminal on that solenoid, crank the engine again. If you now have spark, a problem lays in the instrument cable or some associated item. If still no spark, I'd suspect a failing p/pack.

If at the start of the above, you have a strong blue spark on all cylinders, I'd suspect that due to sitting, the carbs are fouled.... or somehow (and it happens) raw oil has been pumped into the carbs. Remove the bottom brass screws from the bottom front of the float chambers to see what flows out of them. And if the back of those screws are discolored, gummed, whatever, that's a sure sign that they're fouled. Keep us informed.

Joe"

" Thanks for the great tips Jo

" Thanks for the great tips Joe. Here is what I found today. Checked compression, it 100psi+/- 3 for all six cylinders. Thers is no apparent spark with the tester. I disconnected the wiring harness and shorted the solenoid and there is a very weak and intermittent spark with the tester shortened to less than 7/16, probably 1/4 inch. Could this just be a bad connection? I'm going to clean all the connections and pray and try again. Let me know what you think. Thanks again. "

" Joe, Just a couple more poin

" Joe, Just a couple more points. First, I cleaned all the connections and it did not make any difference. Second, I measured the resistance of the stator according to the clymer manual. I read 800 ohms for 1 coil and 775 for the second. The manual says replace the stator if it doesn't read 975+/- 25 ohms. Could this be why I have a weak spark? I replaced the stator a few months ago but I must confess that I bought it off of a used parts dealer. Thanks again! Mike. "

"Mike.... Take a good look at

"Mike.... Take a good look at that used Stator/Charge Coil assys. Those large black coils supply roughly 300v AC to the powerpacks. That charging system runs so hot under the flywheel that the black coils actually melt down, and when that happens, the output voltage drops and the packs will not energize properly. Bottom line, in my opinion, it sounds like that stator/charge coil is faulty. If it's melting down, you'll actually see what appears to be a black gooey substance that has oozed out of those coils .

Due to the fact that you mention that you have absolutely no ignition when the main connector is plugged in to the engine harness, there may be a possibility that a problem exists there also, but then again it may simply be a case that the stator is so weak in output that it can't handle the added resistance etc. Keep me informed.

Joe"

My Force 85 Hp (1987 mode

My Force 85 Hp (1987 model) is having a charging problem. If you check across the battery terminals while its running there is only around 11.7 volts. Shouldnt this be like in a car aprox 13.5 V or so? Its also hard to start. Seems like as soon as a cylinder hits the starter kicks out and its usually just not enough to get it started. I ran some resistance and visual checks on the stator and trigger and they checked out ok. However the voltage readings were low for stator and trigger while running. 40 to 60v instead of 200v. The book indicated that the Flywheel magnets might be bad. Is this a common problem. Where could I purchase a Flywheel or repair magnets/parts if this is the problem. Does anyone suspect a different problem? Also The Rectifier checked out ok with the meter. Any suggestions? Thanks

Dan