Kicker motor problem, cuts out after running for a while

Daveroo

Active Member
I had a problem with my kicker on my last sockeye outing. After running for a while, it would just die. Then it would not start up again. After trolling for a while on my main, I decided to try the kicker again. It started up a ran fine. BNut after trolling for a while it did the same thing. Yamaha 8hp with pull starting.
 
Check your fuel line or filter Seems like the bowl will fill up feeding the carb but is restricted and shuts it down. Left for a bit the fuel dribbles through the blockage and your able to start it up again.
They have an inline fuel filter try changing that and seeing if the lines are clear
 
Check the tank vent. Pick up tube in the tank (remove it). Or i ts possible vapor lock in the heat? when it dies remove a plug and check for spark.
 
check. compression. ...once hot a motor
with low compression will lose the
ability to compress enough to fire
or start for that matter
 

Lol,, pretty general it could be but I don't think so not with it being a heat issue. It may be a fouled up carb with today's gasoline this is a common problem engine shops are making a killing using sea foam these days. Try some sea foam in it or similar product. Don't be afraid to strip the carb off and strip it down and have a look there's really not that much to them. Some needle valves, screens they are pretty simple really. It could be as simple as a spark plug, could be Coil or ECU depending on engine we haven't been told much about it. I doubt it's anything to serious.
 
first check the vent cap on tank..might be vac lock. if nothing obvious drain the carb ,pull it and pay some attention to the jets and needle valve. shouldn't be anything there as you have a clear inline filter on the fuel line ;) . they help you see fuel coming through, no air bubbles and filter the fuel.. sometimes it's quicker and cheaper to change out suspect components.
Check the fuel lines and tank, dirty or for leaks in hoses , how did it stop , gradual die or off as if kill switch.. if sudden then likely electrical.. if slowly (hunting) then fuel starvation likely.
Worn cylinders (low compression ) likely will be more of a low power and plugs get dirty quickly ( you changed the plugs right?)


Don't want to overly complicate or mislead you in diagnosing
I did some yrs ago have a weird problem with an electronic distributor.. it stopped firing when hot. We identified this by starting cold and played a heat gun on the unit it quit within a minute or so, despite motor still being cool..

PIA when they decide to play with us ..
 
Check to see if the fuel primer bulb has gone soft...if so pump it up and see if it fires back up again. Some of the older 9.9's had fuel pumps that would vapour lock once the engine got up to temp. Yamaha put water coolers on most of the pumps to stop this but if an older model it may not have it.
 
Are your motors tied into a built in tank? Sometimes the larger engine creates a vacuum of sorts that prevents the fuel from continuing to flow. An easy check is to run the kicker on a day tank next time out. If issue clears, then you might consider installing an Anderson 3 valve perhaps.
 
Carb
Lol,, pretty general it could be but I don't think so not with it being a heat issue. It may be a fouled up carb with today's gasoline this is a common problem engine shops are making a killing using sea foam these days. Try some sea foam in it or similar product. Don't be afraid to strip the carb off and strip it down and have a look there's really not that much to them. Some needle valves, screens they are pretty simple really. It could be as simple as a spark plug, could be Coil or ECU depending on engine we haven't been told much about it. I doubt it's anything to serious.


A couple of years ago my HT8 which is a 2008 year which I've had since new started running terrible and stalling out. I just took it into the techs and the first thing they said was we'll pull carb first. Sure thing, the carb had sucked up some vanished gas and had got stuck in the float/seat/jets some how. They rebuilt the carb and I've never had an issue since.
 
Check your fuel line or filter Seems like the bowl will fill up feeding the carb but is restricted and shuts it down. Left for a bit the fuel dribbles through the blockage and your able to start it up again.
They have an inline fuel filter try changing that and seeing if the lines are clear
This is going to be my first step I think. Easy to try first and it never hurts to have a new clean filter in place. If the motor can run for about 5 -10 minutes before sputtering does that still fit your scenario? I don't know how long it can run with the amount of gas that is in the bowl.
 
Check to see if the fuel primer bulb has gone soft...if so pump it up and see if it fires back up again. Some of the older 9.9's had fuel pumps that would vapour lock once the engine got up to temp. Yamaha put water coolers on most of the pumps to stop this but if an older model it may not have it.
The motor is a 2002 I think. Is this "an older model". I would consider this as a suspect too because I did have problems priming the gas on the first start of the day. Is the bulb softer? I thought it might have been but I have not been out lately and I cant trust my memory.

But the way thanks to all for the suggestions. I'm learning slowly as I go along.
 
The motor is a 2002 I think. Is this "an older model". I would consider this as a suspect too because I did have problems priming the gas on the first start of the day. Is the bulb softer? I thought it might have been but I have not been out lately and I cant trust my memory.

But the way thanks to all for the suggestions. I'm learning slowly as I go along.

we all are :) everyday..
 
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If it is the fuel pump it would take maybe an hour before it quit the first time as the ambient air temp under the engine cowling has to come up to block temp and then the vapour lock is possible. After it stalls the first time it can happenn again 5 mins later. If yours is stalling out after only 5 mins of running from a cold start it doesn't sound like the vapour lock problem.
 
Coils. They’ll run great till they get hot then your motor will quit. Won’t start again until it cools down then it’ll start and run fine until it’s hot again. To check, run it until it quits, then check for spark. Easy to check and one item off the list of could be’s. only suggestion is do it quick before it cools enough to start sparking again.
 
Clint that could be true for old school motors that used one coil for all cylinders but today's engines have a coil for each...it would still run one coil was faulty..just on one cylinder though.
 
Most Yamaha 4hp and 8hp I have fixed all have the same issue. It's the combination of the fuel efficient Yamaha and ethanol containing gasoline. Drain the carb (Brass screw) and I bet you see flecks of jelly pour out. This gums up the carb jets. When the motor sits for an hour after crapping out, the jelly sinks in the carb bowl and then starts up fine until it gets sucked up again.

By Shell Premium or Co-op marine ethanol free gasoline. The ethanol turns to jelly in 3-4 weeks and causes these issues. You many many need to drain the bowl a few times to get all the gel out. Spraying in carb cleaner will help too.
 
use lots of air when dissembled , soak it all in seafoam for one night
replace the needle and seat !!! , mine was sticking , starving it for fuel at times , would run normal like yours at times , then stall out
with very find sand paper , lightly sand the tiny ribs on your existing needle post , see if that cures it , if your looking for a quick fix !
replace it at the end of the season...
blow it all out very well
mines a bit newer , but runs like a champ , famous for pluggage on these units , ting fuel artery's

check out you tube videos on your model

gd lk

fd
 
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