I got a 12hp nissan works great low speed dies when I give it some gas

[LotsOfishinmyboat]

anybody have any ideas on this problem I got?
at first it would not run at all unless the choke was pulled all the way out so I changed gas and ran some SEA FOAM carb cleaner threw it and it started running fine then I took it out to the lake and started great after just 2 pulls I started cruzing then tryed to give it some gas and it died. started it again and noticed that I had no prime in the ball primed it up and started fine again cruzed at low speed for a bit then tryed to give it gas again and died again.
I'm pulling my hair out as I just bought this motor I hope its something minor that I can fix if anybody has some suggestions it would be great

Thanks guys

T.J.

could it be sucking air/fuel starved
carb still dirty
clogged filter?

thanks again

 

[pvanv]

Re: I got a 12hp nissan works great low speed dies when I give it some gas

"could it be sucking air/fuel starved
carb still dirty
clogged filter?"

All of the above. The carb is likely still way lean, and opening the throttle is allowing too much air -- causing the stall. The carb should be removed, disassembled, and properly cleaned. While the primer bulb probably won't stay hard when running, it should not be full of air. If it is, the air got in there somehow... somewhere between the fuel pickup in the tank and the ball. The fuel line is under suction when running, so even a small leak will allow air in.

 

[Sea Rider]

Re: I got a 12hp nissan works great low speed dies when I give it some gas

Give a good carb clean as recommended by Paul and before you break your head off finding the small air leak into gas system, try engine with a new complete fuel hose, most of the time works miracles with fuel related problems when giving more gas.

Happy Boating

 

[LotsOfishinmyboat]

Re: I got a 12hp nissan works great low speed dies when I give it some gas

thanks for the advice guys I'm glad no one said anything crazy or expencive its kinda what I figured.
I was hoping that I could have gotten away with just running the carb cleaner threw it but knew it might not work totaly.
is there anything I should know before attempting the carb re-build I or is it pritty straight foward.
I'm no mechanic but I got a fair bit of common sence and good at figuring things out hehehe


thanks guys

T.J.

 

[TOHATSU GURU]

Re: I got a 12hp nissan works great low speed dies when I give it some gas

Carb parts for that model engine are no longer available...Beware the money pit.

 

[LotsOfishinmyboat]

Re: I got a 12hp nissan works great low speed dies when I give it some gas

Carb parts for that model engine are no longer available...Beware the money pit.

your kidding me right......

so what happens if I break a gasket or what ever else I can mess up?
is there another carb from another motor model that could fit?
is there things that need to be replaced when cleaning the carb?

wow now you have me scared, should I just not risk it and just have it serviced at the nissan dealership?


a friend of mine said that it might just be that I need to tighten or loosen a screw on the carb it might be running lean or heavy and thats why it dies when I give it gas its flooding out.

ah man I pray its an easy non costly fix I just spent all the money I got on it I wont be able to get another motor this summer

ah well we'll see what tomorrow brings I am gonna try the screw first then if that doesent work I'll try to tear down the carb and give it a good cleaning

thanks for the heads up

T.J.

 

[pvanv]

Re: I got a 12hp nissan works great low speed dies when I give it some gas

T. J.,

No, Elvin's not kidding -- he is exactly right. That motor is older than a lot of mature trees. Very likely 30 years old. However... There is a distinct possibility that an experienced mechanic can go through the carb without needing a kit, maybe, depending on its condition. Yes, if you damage any not-to-be-found parts for the motor, you are out of luck.

Don't just go adjusting carb screws if you don't know what they do. Get some assistance from a knowledgeable helper. Odds are the carb is too varnished-up to compensate it using the pilot screw anyway -- so it likely needs a thorough cleaning.

 

[LotsOfishinmyboat]

Re: I got a 12hp nissan works great low speed dies when I give it some gas

I'm not 100% but I think its an 1987 motor
I was told when I bought it it was an late 80's to early 90's that's why I bought it cause I figured that parts would be easly accesable.
and when I looked up the nissan 12hp for the owners manual the only year I could find that a 12hp was made was 1987. but that motor was NS12C2 and mine is a NS12C2-A
but the motor really does not look more then 10-15 years old it looks brand new
the motor is really clean the wireing looks new the coweling is not faded and only has a couple small scratches the only thing thats banged up at all is the shaft, might have tapped a stump or rock once or twice and lost some paint hehehe
I'm gonna go get it now to bring it in the house so I can check out the carb some more and if I can figure out how to post a pic I'll send in a couple

thanks for your help guys
I'm probably gonna need lots more before this is all running like it should HAHAHA

T.J.

 

[Sea Rider]

Re: I got a 12hp nissan works great low speed dies when I give it some gas

If you managed to put carb 100% operational and still missing when giving more gas, don't forget trying with a new complete fuel hose...Use to believe hoses were timeless, but no, connector inside o'rings experiment air issues with time and use.

Happy Boating

 

[LotsOfishinmyboat]

Re: I got a 12hp nissan works great low speed dies when I give it some gas

yup that might be the next step the hose looks brand new but I did have to replace little rubber O ring where it attaches to the motor it was rotten and cracked.
I just finished tearin down the carb and it was spotless I still sprayed it down with SEA FOAM and sprayed it in every passage I could find.
I had only one problem that I'm not 100% on and that was where a little pointy pin came from I did not see where it fell out of but I think it came from under the wish bone flap that rides on the carb float. it seemed to fit there and it looks like some sort of gas regulator.
Well we'll see tomorrow if I buggered it up I gotta head to work shortly so I cant try to fire it up till then.
oh ya I also cleaned the fuel filter in the gas bubble on the motor.

Jezz I'm gonna be a cirtified mechanic by the time I get this running HAHAHAHA

thanks all

T.J.

 

[pvanv]

Re: I got a 12hp nissan works great low speed dies when I give it some gas

Sea Foam is not carb cleaner, and spraying anything through the carb is not a substitute for a complete disassembly (including jets and emulsion tube), followed by a 4-hour soak in real carb dip such as Tyme.

Sounds like you dropped the needle that sets the fuel height in the bowl (the little pointy pin). You need that part. Don't lose it, or the carb is toast. And then the motor is useless. Maybe you can elicit some local knowledgeable assistance before you have a box of parts. It would help if you had someone who could help you set the float height, for example.

 

[LotsOfishinmyboat]

Re: I got a 12hp nissan works great low speed dies when I give it some gas

ya she is gonna get to the shop if I cant figure it out myself we'll see today once I can get my muffs on her and fire it up.
I defenatly didn't know that the float could be set it looks like it just rides up and down on the post in the float bowl.
and I didn't loose the pin just wasen't too shure where it came from so I put it where I thought it should go, it seemed to fit into a brass fitting under the wish bone flap that rides the float.
like I said I'm no mechanic but I aint too bad at figuring things out.

 

[pvanv]

Re: I got a 12hp nissan works great low speed dies when I give it some gas

There are quite a few things that need to work correctly in order for your motor to run right. For example, setting the float height determines the fuel level in the bowl when the needle is at the shut off/on point. Especially since most parts for the long-obsolete 12 hp models are made of that special material, "un-obtanium", proceed carefully and slowly, and don't be surprised if your efforts are for naught. Some documentation would be a help.

You can download an owner's manual at http://www.nissanmarine.com/tech_talk/owners_manuals.html

If you want to throw some money around, you can purchase a Factory service manual that covers all 1- and 2-cylinder 2-stroke Tohatsu/Nissan motors (of all vintages) from any dealer (including me) for about $45.

 

[LotsOfishinmyboat]

Re: I got a 12hp nissan works great low speed dies when I give it some gas

Well I tore down the carb and cleaned everything I could with the SEA FOAM and while I was takeing it appart I noticed that a large brass bolt just under the wish bone flap was really loose I didn't think that was right so when putting it back together I tightened it up.
So today I put the motor in a tub of water and put the muffs on it primed it up and it started on the 3rd pull.
Man am I ever happy I was getting pritty scared that I had buggered something up expecially that pesky pin that I didn't see where it came from.... I guess I got it back in the right spot.
and that bolt under the wish bone flap that I tightened up didn't mess things up either.

We'll see the next nice day when I can get out on the water but so far so good she is roaring like a lion like all 2 strokes lol

Thanks for your help guys

T.J.

and thatnk for the link to the owners manuel unfortunatly it didn't have my problem in the trouble shooting section but will be good for later problems

and also I made a mistake my motor is a NS12C2 not NS12C2-A not shure if there is a difference

thanks again all

T.J.

 

[LotsOfishinmyboat]

Re: I got a 12hp nissan works great low speed dies when I give it some gas

WOOT WOOT OHHHHHYYAAAAAA she is runnin like a greased weasel just had her on the lake today and what ever I did weather it was the good cleaning with the sea foam or the bolt I tightened down when putting the carb back together it worked and worked well

thanks for all the help guys

T.J

next up the impeller
I watched a few vids on youtube and it don't look too hard
we'll see hehehe