Tanaka 3HP air cooled stalling

[reelfishin]

I came across a new in the box Tanaka 3 HP that I wanted to use on a small jon boat. I took it for a test run the other day and it did fine but every so often while running near or at wide open trottle, the motor just quits, like it ran out of fuel. It restarts instantly and runs fine. If I run at half throttle it runs fine but surges a bit once in a while, I checked the carb, filter bowl and tank, all look fine. The tank vent is a manual screw cap and is clear. The fuel is mixed at 50:1 as in the manual and it runs great up until the abrupt shutdown. It gives no warning, just quits. The part that gets me is that it starts right up, not even a full pull gets it going again and it runs for another half hour or so fine, then it does it again. It's working pretty hard, but pushes the boat about 12 to 14 knots and sounds fine. I have tried just about everything with no change, had anyone had any experience with one of these? I was thinking that maybe the carb or float isn't keeping up with demand or maybe the needle and seat are getting stuck? The part that has me puzzled is that it restarts so instantly and continues.

 

[steelespike]

Re: Tanaka 3HP air cooled stalling

It sure sounds like a fuel supply problem Just a little short when at wot.
when it stalls there is enough flow to restart.Sometimes there is a screen in the tank that could be plugged.Maybe a gas line when hot and vibrating may close up some Maybe something loose in the line.

 

[reelfishin]

Re: Tanaka 3HP air cooled stalling

I blew compressed air through the line, dried and cleaned out the tank, and cleaned and recleaned the carb, filter, and tank valve. The only thing I can figure is that every so often the needle and seat or float stick closed? The float is just a ring of foam that slides up and down, I can sort of picture it getting turned slightly and getting stuck with all the vibration. I tired to run it with the fuel cap all the way off too, thinking that maybe it's a vent problem, but with the motor vibration, at higher rpms it splashes too much fuel out. The motor is really working pretty hard to move me and that boat but it shouldn't run out of fuel. It should at least do as well as an electric trolling motor. I'm not sure though if I like the feel of the centrifical clutch in this thing, I don't think it will last long. It takes too long for it to take hold and start to move the boat. It feels like one of those mopeds or little scooters with a big guy on it, it needs a bit of a push to get going. Once it's moving it moves nicely though, until the motor cuts out. I can go about 6 or 7 miles before it does it, then once I restart it will usually go another 6 or 7 but it has done it over and over a few times, but restarts every time and goes right back to wide open throttle. When it stops, it don't give any warning, it's just a dead stop, no bogging or sputtering. I actually thought that I had turned the motor and pushed the kill switch or something. But the slightest pull restarts it your off. It acts just like when you forget to open the tank vent, only it takes longer to act up. It does seem to do it a little more often when it's hot and it takes a while for the motor to warm up a bit before it will move when cold. The odd thing is that I let it run today in a barrel of water, it never did it once, it only does it under load on the boat.

 

[SirRichard]

Re: Tanaka 3HP air cooled stalling

I am haveing the same thing. What did you do to fix it? I have a TOB-130 Tanaka 3hp. It runs for Hr. or so then it stops and will start up agian. There are some quations on file but have tryed them all. Help

 

[robert graham]

Re: Tanaka 3HP air cooled stalling

I've had a Tanaka 3HP for 25+years now and it sounds like you have a fuel delivery issue. since you've checked your vent screw, fuel line, carb float needle valve, the problem may be a bit of a restriction in that little fuel petcock valve. It has a little hole in it that allows the fuel to pass through when you turn the handle and the hole may be partially plugged or not lining up just right. there's also a little wire mesh screen in that pet **** to clean. you may want to disassemble the petcock and check it out. It's a darn shame they quit making those little motors because they are just the ticket for a canoe, dingy or just as a kicker. mine still runs fine but parts are hard to find and motor requires quite a bit of maintenance to keep it running just right.

 

[robert graham]

Re: Tanaka 3HP air cooled stalling

another thought and a quick fix, since I've been dealing with this little motor so long, unscrew that little plastic fuel bowl, remove the wire mesh screen, open the petcock and stick a straight piece of wire(like a coat hanger) up through the hole to be sure it's open and you get a good strong flow of fuel out of the hole. close petcock, put it back together and you should be good to go. I even carry a piece of wire in my tool kit just for this purpose. Good Luck!

 

[SirRichard]

Re: Tanaka 3HP air cooled stalling

Thanks for the come back. I am working on it in my spare time and will let you know how things work out

Sir Richard
.

 

[robert graham]

Re: Tanaka 3HP air cooled stalling

as I mentioned, I've got 25+years experience with that little motor and will be glad to help you out any way I can. I've even thought of replacing that little petcock with another design, maybe a plastic ball-valve unit. That petcock that comes on the motor is not the best design, in my opinion.

 

[SirRichard]

Re: Tanaka 3HP air cooled stalling

Hi

Well I got at it the other day and yes it was bad. So I clean it up and put it back together. I turn down the ital some so it would not turn the prop. Took it out to give it a try and it would only Run for one min or more. I am at my wits end. I ck the fuel line from the tank to the carb. and it look ok with some loss of stream. What next???????????? A big thanks to you for your help but wont to get this 3 hp runing so I can do some fishing and crabing.

Thanks alot
Sir Richard

 

[SirRichard]

Re: Tanaka 3HP air cooled stalling

as I mentioned, I've got 25+years experience with that little motor and will be glad to help you out any way I can. I've even thought of replacing that little petcock with another design, maybe a plastic ball-valve unit. That petcock that comes on the motor is not the best design, in my opinion.

WoW I got it to run. I only did two things to it the last tiime I worked on it. Clean the carb and turn down the itel. Well, I turn it back to where it was apx. It started on the 3th pull.but runs fast. What does the itel setting have to do with the running of the motor??????????

 

[kevinkearns]

Hi Everyone,

Your posts on this subject are 9 years old, but I am hoping very much that you are still part of this forum because I have EXACTLY the same problem, including the mysterious situation of the motor running fine in a tank but stalling under load of the boat. However, in my case the stall comes after only about 20 seconds under throttle. The engine starts easily and idles perfectly. I too am at wits end.

Please help if you can.

Many thanks,
Kevin Kearns, Pittsburgh PA

 

[GA_Boater]

Hi Everyone,

Your posts on this subject are 9 years old, but I am hoping very much that you are still part of this forum because I have EXACTLY the same problem, including the mysterious situation of the motor running fine in a tank but stalling under load of the boat. However, in my case the stall comes after only about 20 seconds under throttle. The engine starts easily and idles perfectly. I too am at wits end.

Please help if you can.

Many thanks,
Kevin Kearns, Pittsburgh PA

The best way to ask for help is by starting a new thread. After all this time, it is a little late to ask for follow-up. Thanks.

Closed.