89 30hp missfire after 10min warm up

[wormz]

Re: 89 30hp missfire after 10min warm up

i know im sure learning alot from you guys! this has to be the best site for boaters ive found. everyones pretty honest and helpful!

i have a coil on the way. sent my wife after it and we will soon know!

 

[wormz]

Re: 89 30hp missfire after 10min warm up

nope....coil no fix! atleast it was only $25

any other suggestions? do flywheels go bad?

 

[flabum]

Re: 89 30hp missfire after 10min warm up

K. this ignition system consists of:

1) Charge coil
2) Powerpack/pickup assembly under the flywheel
3) 2 ignition coils
4) Temp switch for the S.L.O.W. hooked to power pack
5) Kill circuit (black/yellow wire)

Simple setup.

By disconnecting the temp switch, you eliminated the possibility of that being bad and trippnig it into SLOW mode.

The power pack has the circuitry for the SLOW, but you have already changed that.

You changed out 1 coil and still have the problem.

The only thing you have not changed is the charge coil. The charge coil is under the flywheel and provides the energy to the powerpack.
Locate the two wires (bullet connectors), get the engine to where it starts acting up and quickly shut it down and ohm out the charge coil while it's still hot.

 

[wavrider]

Re: 89 30hp missfire after 10min warm up

getting there, that is the only thing left, charge coil, hopefully it will just be a corroded connection, clean them and maybe ??? Great thread.

 

[wormz]

Re: 89 30hp missfire after 10min warm up

New charge coil. same bat time same bat channel!
i got new everything on the list above, except the flywheel.
i never heard of the flywheel doing this. not really sure how sensitive the magnets are in there, being ive seen them pulled form the salt water and the flywheel was never changed out i figure they are tough.

timing light shows both coils have no spark until the engine winds down to low rpm, fires once and it waits again until the rpm drops. both plug wires are new, coils been replaced(one by swapping both),power pack, charge coil(under flywheel), plugs are new.
ive unhooked the temp switch.
rebuilt carb,new fuel,different tanks
im missing soemthing somewhere.

im reaching way out for this one......

if the t-stat is stuck open, it never gets warm, not even 80 degress. does the power pack have logistics to say something is wrong and kick it into S.A.F.E. mode?

i also have an idea to put a resistor in the place of the temp sensor and make/force it to thinking it needs to go into S.A.F.E mode to see if it is the same kind of fault or condition.

 

[Harker]

Re: 89 30hp missfire after 10min warm up

Wow, when this thing starts working, you will have a new engine. Check,clean and tighten all electrical connections and ground wires. Terminal block isn't shorting out? Stator tests ok? Getting down to some three cent item here.

 

[wavrider]

Re: 89 30hp missfire after 10min warm up

Flywheel,

I need look the manual for this one,

The flywheel might want to clean the magnets, if any corrosion on them.

Unless the magnets have lost there polarity they should be good.

Is there any adjustments that can be made for the charge coil to how close the setting is to the flywheel? the gap between the charge coil and the flywheel.

This is a mystery!!

Just for curiosity sake disconnect your stator from the rectifier, if you have a bad rectifier you could be putting alternating curretn to your powerhead if the diode shorted out in the negative side of the bridge, a/c on ground can cause some wierd stuff to happen.

 

[flabum]

Re: 89 30hp missfire after 10min warm up

The stator and rectifier has nothing to do with the ignition system. None of the wires except the ground is connected.

As for a flywheel being bad: I would seriously doubt it, but when I was in Evinrude school, they had a bad flwheel on a motor to show us what it would do, so it is not unheard of. And since the powerpack was scraping against it, the magnets could have been hammered and lost some of their strength. Anytime you hit a magnet with a hammer, such as when removing the flywheel or something hitting it as it's running, the strength of the magnet deminishes. I'd hate to see you spend more money if it's not the cause, but you have changed everything else. At lest you have a bunch of good used spares.

 

[wormz]

Re: 89 30hp missfire after 10min warm up

im not against spending the money on it...just dont want to pay the dealer to say they couldnt find it again though. so far ive only spent in parts what they have already charged me to diag it and still not find it.

something has to fix it.

im going to try and unhook stator to see what that does. that will take it out of the loop.

then im going to try cleaning(even if already is) all grounds and otehr conncetions. (most are new by now)

what you guys think next? im ok with far out explanations at this point!

 

[HighTrim]

Re: 89 30hp missfire after 10min warm up

Im going to jump back a bit again.

Could you post a pic of the flywheel and magnets?

 

[ezeke]

Re: 89 30hp missfire after 10min warm up

This is a little repeticious, but maybe worth saying.

Disconnecting the temperature switch at the cylinder head will not disconnect the rest of the tan wiring from the power pack, but there is another disconnect on the tan wire that is closer to the powerpack that will.
Powerpacks withe S.L.O.W. are triggered by the temp switch and also by VRO or OMS functions. This cuts out half the cylinders, so they will not fire.
If the temp switch is faulty, it can trigger S.L.O.W. at lower temperatures than it should.
On remote electric start systems there is a blocking diode in the harness to prevent S.L.O.W. from activating erroneously.

 

[wormz]

Re: 89 30hp missfire after 10min warm up

BREAKTHROUGH!!

temp sensor is making it go into S.A.F.E. mode. but something is shorting making it read bad. with the engine off the sensor has the correct resistance, with the engine running after 15 minutes, it goes haywire the resistance goes up and down drasticly.

now i know why it didnt make a difference when i would unhook it. once in S.A.F.E. mode, it has to be cut off to reset the power pack logic to go out of safe mode.

the the engine is definately not overheating. its luke warm to the touch.
i havent unhooked the rectifier yet, ill do that now to see if its got the bad diode shorting through causing the temp sensor to go crazy.(ive seen an air conditioning diode bad on a car once and it caused the digital mileage to show 600,000 miles so i know it can do wierd stuff)

 

[ezeke]

Re: 89 30hp missfire after 10min warm up

BTW, what is S.A.F.E. Mode? Is that a homegrown name for Speed Limiting Overheat Warning or S.L.O.W.?

If you have a remote system or other than a straight tiller system, unplugging the temperature switch at the powerhead will not disconnect the whole tan wire system from the powerpack.

 

[wormz]

Re: 89 30hp missfire after 10min warm up

i guess, yea S.L.O.W. warning might as well be safe mode!

 

[wormz]

Re: 89 30hp missfire after 10min warm up

ok, with the rectifier unplugged.... no cut-out. runs fine with everything connected. soon as you hook up the wires to the rectifier... goes into S.L.O.W. mode.

must be shorting with heat?? who cares. boat shop said it be couple days to order, i feel good about it! if i can find a diode, ill wire it in to see if that works before actually ordewing a new one.

it has been running now for near 40 minutes at half throttle.

ill post back when i get a diode or a new part!

thanks a bunch WAVRIDER for the off the wall idea & everyone for the struggle!

 

[patrick4266]

Re: 89 30hp missfire after 10min warm up

Sounds like you about got it figured out. These electrical problems can be very wierd. I have heard of cars being tuned to a certain radio station while using your left turn signal and honking the horn would cause them to die.

 

[wormz]

Re: 89 30hp missfire after 10min warm up

yea, its been crazy... im more glad that it wasnt an "easy fix" that was just as easy as saying hey stupid, you forgot to hook up the kill switch! i sure know ive overlook things before.
i hope this may halp apoor sole int eh future...now if we ever hear of this again we will all jump to say "check the rectifier!"
lol

 

[patrick4266]

Re: 89 30hp missfire after 10min warm up

You have got to learn a lot and so have I from just reading your post. As I said I am not a outboard mechanic but I have been reading most post just to learn for future use.

 

[wormz]

Re: 89 30hp missfire after 10min warm up

yea, im with ya, ive been a tech for a while at a GM dealership and 2 cycle is a bit different game.
its nice knowing a little about it. very fortunate to have the people on here with the knowledge and willingness to help out!

 

[wavrider]

Re: 89 30hp missfire after 10min warm up

Your welcome worm but it was a combined effort.

My career training is in electronics, outboards are just a hobby, a GREAT hobby. I prefer to work on them more than I do to drive the boat, unless fishing of course.

It was just not making any sense how your electronics kept getting wierd, so I thoght sure fuel related, after you eliminated that then it made me go into "tron mode", came up with the idea of the shorted bridge.

someone posted a rectifier has nothing to do with ignition? It doesnt until it shorts and puts an alternating curretn on the ground side of direct current.

Alternating Current will ride on top of direct current, ground or positive, use it all the time in filiments of transmitting tubes where 3 or 4000 VDC are on top of the tube and 5vac to light the filiment up. AC does wierd stuff.

As far as the rectifier, order OEM or go to Radio shack, get a 10amp bridge for around 8$,, 2 ac inputs from the stator, negative dc to a ground and positive to your solenoid

got a couple here lke that, been running one over 3 years no problems