9.9 yamaha issues

[frayedknot]

I have a 4 stroke hi thrust 9.9 yamaha that has me stumped with an issue.

It will start good and run about 5-10 mins and then stall . can restart and then stalls again ,and again ........

Leave it for 5 mins it will start and run all day like a timex !!! WTF

when it stalls the oil light always goes out first !!

I have replaced the oil pressure switch .

What else the CDI box? how can I test ? or does someone have a used one to BUY or tryout before I buy new?

Any ideas welcome as I am done with this motor right now !!

Cheers
Greg

 

[SteelyDan]

Could be a bad O ring on your fuel connection. I suspect there might be air in the fuel... When it stalls is the primer bulb hard or soft?

 

[trophywife]

Yup , sounds like, burp, air.

 

[profisher]

It won't be fuel if it runs all day after going through the stall phase. If it were fuel it would have the same symptom continually...it wouldn't just get better on its own. normally with a cdi box it will act up once the engine heats it up and there is expansion internally causing a weak solder to loose contact. Yours is the opposite as it runs when warm. If this was a winter symptom when temps are close to freezing...your engines symptoms are classic carb freeze up. I'm guessing it is acting up now not winter?

 

[MOBY DICK]

I have a 4 stroke hi thrust 9.9 yamaha that has me stumped with an issue.

It will start good and run about 5-10 mins and then stall . can restart and then stalls again ,and again ........

Leave it for 5 mins it will start and run all day like a timex !!! WTF

when it stalls the oil light always goes out first !!

I have replaced the oil pressure switch .

What else the CDI box? how can I test ? or does someone have a used one to BUY or tryout before I buy new?

Any ideas welcome as I am done with this motor right now !!

Cheers
Greg

Had the same problem with one of mine so first thing down to the boat dropped it in the water and ran it while getting all the tackle out until it stalled then pulled it back up ran out dropped it again no problem. Was a bit of a pain lifting x2 instead of once got me thru the summer. When it finally would not start at all turned out to be the stater, replaced it with a used one no more problem.

 

[frayedknot]

Thanks for the replies .
I have been through the fuel system and don't believe it is fuel related anymore.
Yes it is doing now it will do it all year long , but worst in the winter .
I have been warming it up at the dock at the same time as the main. Then running out and fishing . what a pain the A$$ !!!
That"s what I"m afraid of one day it won't run .
I'll Check into the Stater .

Thanks again

Greg

 

[profisher]

If it stalls shortly after getting it running and it when it quits it starts to sputter and slowly die out then it may just be what mine was. These motors come with a set idle mixture screw which is hidden behind a brass plug pressed into the carb. My mechanic drilled out the brass plug which exposed the idle set screw. He riched it up slightly and now mine doesn't stall out during the warm up process. It starts right away without a lot of cranking and keeps running. It may stall once but not every time. It is way better now. They preset these engines to a lean mixture setting that doesn't always work for every application. High elevation, low elevation etc would require the ability to adjust this mixture.

 

[frayedknot]

The first time it stalls it takes about ten minutes . It doesn't sputter it just dies , Will restart right away but only run for a short period Less than 30 seconds, some times less than 2 seconds .It will do that for about 5 minutes and then it will run all day . It never sputters it just dies . Last time out and in the driveway for test lately I have noticed that every time it dies the oil light goes out 1-2 seconds BEFORE it dies .

I though for the longest time it was fuel and have done everything with fuel related ,plus new thermostat ,oil pressure switch , now I am stumped !!

I looked at the wiring diagram and both the CDI unit and the Stator both connect to the oil light and switch ?

Thanks for the feed back . Profisher

Greg

 

[profisher]

If it just dies like you turned off the key then it is an electrical problem. My knowledge of how the stator could be involved in your problem is not enough to give advise.

 

[frayedknot]

Ok so I'm still trying to figure this out !!
Have been running the motor everyday with ears on in driveway ( I'm sure the neighbours love it ).
It has been getting better less stalls not having to let it and wait with it not running etc.
yesterday it didn't stall at all ran right through no problems 1 hour .
today 7 mins in it stalls first time then 30 seconds 20 -10 then wont run more than 2-3 seconds oil light will not come on let it sit 10 mins . Start it and it runs perfect for 30 mins .
Does it have to do with last nights rain and moisture in something ??

Does somebody have a mid 90's Yamaha that there are parting out that I could BUY or try the CDI or STATOR .

Thanks
Greg

 

[frayedknot]

So I found a used stator and it fixed the proplem .
Was out today ran perfect love my boat again!

Thanks for the tip MOBY DICk

Greg