1998 johnson 3 cylinder 35 hp

[JoshKeller84]

Re: 1998 johnson 3 cylinder 35 hp

can this be done with the boat on the trailer, backed into the water? thanks

 

[Daviet]

Re: 1998 johnson 3 cylinder 35 hp

Yes, as long as the engine is under load, do not run your engine wide open with no load on it, you might not like what might happens.

 

[JoshKeller84]

Re: 1998 johnson 3 cylinder 35 hp

ill ask my mechanic to borrow his timing light. if i cant get ahold of him, will the test be doable by using my spark tester grounded to the spark plug?

 

[Daviet]

Re: 1998 johnson 3 cylinder 35 hp

I guess if you feel like pulling plug wires with the engine running wide open, I don't , been there done that. Took quite awile to get feeling back in my hand after getting snot knocked out of me.

 

[JoshKeller84]

Re: 1998 johnson 3 cylinder 35 hp

so this isnt something that can be tested one at a time, shut motor off, then test another?

 

[Daviet]

Re: 1998 johnson 3 cylinder 35 hp

No, you need to test the plug wires with the engine running under load and wide open throttle to see if you are dropping a cylinder under those conditions.

 

[JoshKeller84]

Re: 1998 johnson 3 cylinder 35 hp

much appreciated. heading over to get timing light now.

 

[Daviet]

Re: 1998 johnson 3 cylinder 35 hp

Let us know what you find out.

 

[boobie]

Re: 1998 johnson 3 cylinder 35 hp

You can put a timing light on a cylinder and it will show you it has spark and that's it. When you pull a plug wire that will tell you if it's running on that cyl or not. Power drop, running. No power drop, not running. Could be a fuel prob if no drop.

 

[JoshKeller84]

Re: 1998 johnson 3 cylinder 35 hp

i did check on the water to see if i could isolate a cylinder dropping when going wot by removing one plug wire at a time. all had a noticeable drop - this motor just will not get above approx 2500 rpm, whether in water on even on garden hose. almost makes me believe its going into slow mode.

 

[hidef]

Re: 1998 johnson 3 cylinder 35 hp

I watched your video and I believe your engine is going into SLOW Mode. Unplug the connector with the yellow/black, tan, tan/yellow and white black wires going into the power pack. If that cures the problem, you either have a bad temp sensor, or the tan wire that was connected to the oil sending unit is grounding out. If it doesn't you might have a bad power pack.

 

[JoshKeller84]

Re: 1998 johnson 3 cylinder 35 hp

is a symptoms of SLOW mode a shaking engine? if unplugging this connector does solve the problem, is there any reason i cant just run the motor without the protection of the slow mode?

 

[hidef]

Re: 1998 johnson 3 cylinder 35 hp

Yes the engine will shake when in SLOW mode. Unplugging the connector removes the wiring and the sensors from the loop but it also removes the kill wire (yellow/black) which is used for turning the engine off. If disconnecting that connector solves the issue the next step is to isolate what in the harness is causing the problem.

 

[JoshKeller84]

Re: 1998 johnson 3 cylinder 35 hp

Unplugging the plug definitely prevented it from going into slow mode... I believe my problem has been determined. Any tips for troubleshooting? Snip the wires at the connection and just leave the kill wires hooked up?

 

[hidef]

Re: 1998 johnson 3 cylinder 35 hp

I would cut the tan/yellow wire at the connector going into the power pack. That wire is used for the low oil / no oil monitoring circuit. Try cutting that one first. If it works that is your problem if it doesn't your can unplug temp sensor from the harness (follow the white/ black and tan wire) to the the sensor. If that works then you need to check the temp sensor to see what is wrong with it.

 

[daselbee]

Re: 1998 johnson 3 cylinder 35 hp

Cut??!! Why? Disconnect the connector, and measure each individual suspected wire to ground with an ohmmeter, checking for continuity that should not be there.

 

[hidef]

Re: 1998 johnson 3 cylinder 35 hp

The tan/yellow wire is strictly for the Low Oil / No Oil warning circuit. He has removed the oil tank and mixing chamber and if hasn't he better because it is junk. Cutting that wire removes any possibilities of issues down the road as it is no longer needed or required once the oil tank is gone.

 

[JoshKeller84]

Re: 1998 johnson 3 cylinder 35 hp

ok, checked the resistance at the powerpack plug and determined it to be the temp sensor. I followed the wires up to the plug by the oil tank plug, and checked the sensor direct and it too had continuity. bad sensor? if i install a water pressure and/or remote temp gauge, can i just bypass and leave unhooked?

 

[hidef]

Re: 1998 johnson 3 cylinder 35 hp

The temp switch should have the following Ohm readings

white/black to ground below 90 degrees open closed at 105
tan/blue to ground below 207 degrees open closed at 240

I would replace the switch.

585023 — TEMPERATURE SWITCH (1 required per assembly)

With the 4 wire connector plugged back into the power pack and the temp sensor unplugged from the wiring harness does the engine go into slow mode?

 

[JoshKeller84]

Re: 1998 johnson 3 cylinder 35 hp

no sir, it does not. i tested both wires coming out of the switch and both were showing continuity. tested all of the oil warning wires and all were open. verified plug was making good contact by making sure the key switch turned off the motor, which it did.