89 30hp missfire after 10min warm up

[flabum]

Re: 89 30hp missfire after 10min warm up

Disconnect the temperature switch from the power pack and see if the problem goes away. A bad temp switch will throw it into S.A.F.E. mode.

 

[wormz]

Re: 89 30hp missfire after 10min warm up

it just takes longer with the top off..kind of determines heat build up...i see where your going witht he exhaust.
i dont feel thats the problem by the way its acting... it doesnt choke out..it cuts off like a rev limiter.


i have disconnected the temp switch...no change (third thing i tried)

 

[wormz]

Re: 89 30hp missfire after 10min warm up

i have attempted to use a heat gun on many components, cant seem to get it to act up.
i like the idea of the timing gun on the plug wires, im going to try tha next...i have to pull my boat indoors to do so as its raining and cold....real cold! so it may be tommorrow afternoon till i get to it.

 

[Harker]

Re: 89 30hp missfire after 10min warm up

What's the compression? Is it electric start with an electric choke solenoid? Have you disconnected the kill circuit and tryied running it? Just trying to think of stuff I haven't read yet....have you rebuilt the carb? When the motor stops, it feels warm and not hot.It just cuts out from wot to idle and doesn't die? Did you retorque the flywheel (since you said it comes off easy it kinda raised a flag).

 

[wavrider]

Re: 89 30hp missfire after 10min warm up

I read and re-read the posts. I think ezeke has probaly got it,, it sounds lust like a little varnish or gum on the float or the seat, intermittent fuel supply. can run for few minutes or few hours then make it mess up, idle it down bowl fills with gas and off you go again, or a weak fuel pump sucking air from a gasket. Yah you chasing some demons, you have about eliminated everything in the ignition,

Look at that carb once again, take it apart, clean it and if have compressed air blow it clean, if no comporessed air maybe possible to find some, friend, auto garage anything but get it clean.

 

[wormz]

Re: 89 30hp missfire after 10min warm up

carb is now cleaned and looks good. no trash in bowl.
it feels warm if not cool to the touch even after 30 minutes of running.
the flywheel is easy to remove because i have the tools to do it...it definately takes a puller to remove it.
yes, does not die, just drops to lower limit, if i hold it WOT it will sound like a rev limiter and "bump" (not a good word for it) until it gets back down to the speed of just above idle.
it idles great when it is acting up, i can even start to make a wake up to a 1/4 throttle....any more throttle than 1/4 to WOT it will set on a limiter feel and not allow more rpm, just like cutting off a kill switch. until it gets lower.
it honestly sounds like a car at a 4k rpm rev limiter witht he car floored at idle.

 

[HighTrim]

Re: 89 30hp missfire after 10min warm up

Just going to throw a thought out there....

Have you tried testing the warning buzzer (standalone or not??)?

Could it be going into SLOW mode, or having a fuel restriction, yet you just cannot hear the horn since it is not functioning (if there is a horn)?

 

[wormz]

Re: 89 30hp missfire after 10min warm up

i can spray fuel into the carb when it is acting up, it doesnt change, if anything it chokes out like its flooded when i do it. i dont think its fuel.
im trying to do the timing light thing, i have plenty of tools/shop to do the things needed to test it, just not very knowledgable in outboards. its hard to give it twist of the wrist to get it to act up and use the timing light at the same time.

do you think something HARKER? "It just cuts out from wot to idle and doesn't die? "

 

[wormz]

Re: 89 30hp missfire after 10min warm up

no buzzer here. its a standalone unit. has the twist throttle with a kill switch and a fuel lne is about it.

im hearing alot about S.A.F.E. mode. any way to know if its in S.A.F.E. mode?

 

[HighTrim]

Re: 89 30hp missfire after 10min warm up

SLOW is the speed limiting overheat warning

The circuit is activated at 203 deg F. When activated the engine RPM will be limited to approx. 2500 RPM.

But as Flabum said, disconnecting the temp switch at the Power Pack would eliminate this.

 

[wormz]

Re: 89 30hp missfire after 10min warm up

ok gothca. i unplugged it and it didnt change. i checked the reistancce on it and by the chart it dont get but to 80 degrees F. unplugged it suppose to like -40 so no trouble there.

 

[Harker]

Re: 89 30hp missfire after 10min warm up

I would do a rebuild on the carb and fuel pump. Blow the hoses out to get any crud that may be in them out. On the carb rebuild, take it ALL apart and soak overnight in carb cleaner then blow carb cleaner through all the little passageways..put a new fuel filter on if it has one and get the rebuild kit with a new float.Check the pickup screen in the tank too. If it will run all day at idle without a hickup I think it must have a flap of crud that works it's way into a fuel passageway when fuel is being pumped at a higher velocity.If it has an electric primer or choke, make sure it isn't activating at wot too. Did you say it's an electric start? Is the new powerpack an rpm limiting pack? You aren't running too small a pitch prop and over revving are you? Just ideas on this gremlin.

 

[wormz]

Re: 89 30hp missfire after 10min warm up

keep the ideas coming by all means.
im cleaning the carb now, new kit be here this afternoon with float and ill soak it for about 8 hours.
fuel tank eliminated, iswitch tanks between three of them...no change.
i have a friend coming to help with a timing light to see if its fire or fuel.
does not have electric choke, is electric start. im positive its not overreving.
seems temperature/time related(like swelling/breakdown or fuel blockage as you guys stated.)

 

[ezeke]

Re: 89 30hp missfire after 10min warm up

The clip helps the float regulate the opening and closing of the float valve. It connects the arm of the float to the needle. Click the thumbnail:

 

[wavrider]

Re: 89 30hp missfire after 10min warm up

Tried 3 different fuel tanks, have you tried a different fuel line, primer bulb, possable trash in fuel lineor primer bulb also

 

[wormz]

Re: 89 30hp missfire after 10min warm up

ok, yea, got the clip that holds the plunger on there.
new prime rbulb and fuel fitting on the engine(new spring shut off so it holds fuel from leaking down.

 

[patrick4266]

Re: 89 30hp missfire after 10min warm up

Just to throw in my two cents. First of all I am not a outboard mechanic, but I am a auto machanic and I have been working on cars since i was a teenager, 58 now, anyway certain things apply to all engines. Over the years I have seen a few coils go out, not that often but it does happen. From reading all the comments it sounds more like a weak coil getting weaker as the engine warms up. I, like every one else am curious to what it is so keep us posted.

 

[wormz]

Re: 89 30hp missfire after 10min warm up

ok, got the light hooked up(timing).
it does drop out, when its acting up it has no spark, unitl it drops to lower rpm, then it sparks as steady as the wind.
i cut off the engine and start it back, 20 second shut down, start it up and it runs fine for another 5-10 minutes any rpm. then all the sudden Drop out rev limits to just above idle.
im in the right path now...im no expert either but how is the magnets suppose to look in the flywheel? can any schratches cause a breakdown this sudden?

so basicly im looking at a coil under the flywheel that supplys the power pack or a flywheel??

thanks guys for the fast responses!

 

[patrick4266]

Re: 89 30hp missfire after 10min warm up

Glad you found out it was electrical as i figured it was. Too bad you do not have a spare coil to throw on it. I was able to buy me a spare motor, same hp ect as mine along with a boat, controls and real nice trailor for 300. I got the engine running real nice as I was able to swap parts and figure out why the motor I bought did not run. That way I do not have to spend money on parts in the "guessing game". Some of these guys may be able to tell you if there is a way to test he coil.

 

[wavrider]

Re: 89 30hp missfire after 10min warm up

One charge coil in this ignition, one power pack, two coils, swap coils, se if the problem follows a coil before throw any more parts at it, also look at all connections from the charge coil to the power pack, from power pack to coils see if any are chaffed or shorting to ground. you just about got it licked