Yamaha 8hp problems

Jimmy

Member
I have a 3 year old Yamaha 8hp 4 stroke high thrust long shaft pull start. this motor ran fine the first two seasons. in the last year it has spent more time in the shop than on the boat.

The motor will start with the choke and fast idle but when i idle it down or put it in gear it will stall. It will do this a few times and then it will die and not start again. I have had it into two different shops and had the carb rebuilt several times cleaned out several times. I have run this motor on a separate tank and had the same problem. Each time i get it back from the shop and i am told it is working it may run for a while before these problems happen or it may not work at all.

In July i tried to buy a new carb for it and called around all over and found out that the carbs for this model were on back order and could not be found in BC or washington state.

Now Yamaha does not make this model anymore they now have replaced it with a 9.9. I don't know if this is because they have had problems with this model?

Has anyone on here had these problems with there yamaha 8hp & if so what did you do to fix it. Or do I have a lemon?

I have owned three other yamaha kickers and never had a problem.

Thanks in advance for any advice this royally Screwed up my fishing season this year.
 
Sounds like a great time to put it on cragslist
 
, first issue ever on my T8 this summer , i believe it was caused from water that got through the fuel system ,
last fall , and perhap some dirt or debris of sorts , my mechanic worked on it a few times , somewhat the same symptoms as you
, i changed the needle and seat ,was sticking.... runs perfect again , cheap part , wont hurt ta give it a shot , my guys kept pulling the carb apart and blowing it out and cleaning it , run good for an hour or 2 , and eventually it would just die ,

runs perfect again...has been a solid motor for me....

gd luck

fd
 
My T8 always ran great until 2 years ago. Took the carb apart and cleaned it about a dozen times with the same results should described. Finally found there was a tiny piece of crap in the inlet to the carb that I couldn't get rid of. Ended up buying a new carb via Internet and all is well again. I added an extra in line fuel filter to keep it from happening again. Great engine, mine has around 1500!

Sent from my SCH-I545 using Tapatalk 2
 
Sounds like a great time to put it on cragslist

I tend to agree. I couldnt look somebody in the face as say it works and if i could i doubt it would run/start if somebody wanted to see it running.

Thank you for the advice Fog Ducker & Almar 22. I will try it out. I am getting sick of paying $300 every time I take it to the shop.
 
Definately a micro debris problem... It is using up the fuel in the bowl and then starving for fuel.
 
I have the 9.9. Never liked it from day 1. The new ones are not anywhere as good as the old big block 9.9's. Same issues. It's crap in carb for sure. One little cheap trick that sometimes works is to run that thing full out in neutral, then pull manual choke until she almost stalls, repeat many times. It creates strong vacuum and sometimes if you're living right will suck that crap out of there. Otherwise, do what FD says. They are JUNK in comparison to the older yami's. Why they had to mess with a great engine is beyond me. I'm waiting until Suzuki comes up with remote, power tilt 20 hp kicker and that grey POS is GONE.
 
I have feeling you are not waiting long enough for it to heat up.... If it the same problem I had it will stall.You will keep trying to pull start and it will flood. I bet you it will restart after 5-10 minutes or so.

Whats your start up procedure? Mine is T8 same year. It is hard starting. Always has been from brand new. I place throttle half way and choke out full. 2-4 pulls to start especially when cold. Once started put choke half way for maybe 15 second... than I just let it run the motor will let you know if too much choke starts to try to stall. If I start using I don't engage it forward far at least 3-5 minutes.... I most of time now make sure it is fully warmed up before taking boat out. Funny thing is once its heated up it will start all day one pull no problem..

I have never been able to throw it in start position and just started it up it doesn't work.

As cleaning I only once had a hug issue with fuel...and water had gone into carb. Had it cleaned and everything is good now...Its been very reliable for most part.

Profisher or Wolf can way in they use these motors a lot....

Thank you for the advice High Five but I have experienced exactly what you described with my previous yamaha 6hp and this 8hp as well. If it was only what you are describing i could live with it and at least fish.

I have to agree with searun on this one I hate this motor every time they clean or rebuild the carb they say they found a little debri or water. My aluminium tank has been cleaned three times I have now installed an in line racor style filter. Rebuilt the carb put new gas in the tank with yamaha fuel stabilizer all done by a yamaha dealer and i am still having the same problem. It seems even the yamaha dealer can not figure it out after several visits to them. I don't know weather to take it back again to the dealer or kick it over board and cut my losses.
I have owned 6 kickers in my life and never had such an unreliable motor as this lemon.

Now i am getting worked up. Thanks for letting me vent feels good......:)
 
My experience:
I have the 2003 8 hp HT manual start and it has been absolutely a flawless motor. Always starts, even after storage for the winter quite often it will start on the first pull, it runs quietly, no vibration, no smoke and it sips gas.

To start while cold:
1 - squeeze the primer bulb with the outlet end up until it becomes firm
2 - place gear shift lever in neutral
3 - place the throttle control grip in the "START" position
4 - pull out the choke knob completely
5 - pull the starter rope slowly until you feel resistance and then give a strong straight pull on the rope to start engine
6 - if it doesn't start on the first pull it almost always starts on the second pull
7 - once the engine is running, after about 3 to 5 seconds I push in the choke about 1/2 ways.
8 - after about 30 seconds I will push the choke in all the way and then adjust the throttle to the idle speed.

For storage;
1 - I run the engine and then pull the gas line on the engine and run it until it stops
2 - just before the engine stops running I give the carburetor a few short shots of storage seal (this will cause the engine to smoke and it may want to quit)
3 - remove the drain plug on the carb bowl to drain any remaining gas
4 - remove the plugs and give each cylinder a good shot of storage seal
5 - replace the plugs and turn the engine over a couple of times
6 - change the inline fuel filter
7 - change the crank case oil
8 - change the oil in the leg
9 - grease all the fittings
10 - pull the prop and regrease everything
11 - wash off the motor and wax it
12 - Take motor off the boat and store it upright
 
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