Carburetor Issues

[MacFern]

My 8 hp kicker will not run without me constantly pulling out the choke and messing with the throttle. This happened before and for about $100.00 the dealer’s mechanic cleaned the carburetor and it ran fine – for a while. Their advice was to use the motor more often. I would love to do that, but probably won’t. I am curious why this is the only motor I’ve ever owned that has this problem. Also, is cleaning the carburetor easy to do yourself? Is this something a fuel additive might fix?

 

[Brent]

I add SeaFoam to gas.
Darn mower always starts too :wink:

 

[DaleH]

Remove carb, turn needle valve IN (counting number of turns, e.g., 1-3/4 or whatever), then remove it. Place carb in strainer basket that comes with ~$20 "Carb Klean" at local auto parts store, don't immerse for a long time - read the container. Get injector/syringe and force same solvent through all passages. Remove and blow through with compressed air, from smallest to larger orifices.

Re-install and she should be fine. I've done the Seafoam trick too and it works on 80% of them, when it doesn't ... I now do what I wrote above.

 

[MacFern]

Thanks. I start with the Seafoam, and if needed I'll follow your very clear, simple instructions.

With the Seafoam are you referring to the decarb process that I've read about somewhere on the forum, or am I able to just add a little to the gas and run it like normal? If it's the 2nd option how much Seafoam is needed?

Thank You!!!

 

[DaleH]

With the Seafoam are you referring to the decarb process that I've read about somewhere on the forum, or am I able to just add a little to the gas and run it like normal?

You want Seafoam here to sit and dissolve any fuel crud ... not to do a decarb.

1) Run OB 'dry' on existing fuel line, disconnecting fuel line from tank once she's started
2) Drain carb fuel bowl to ensure empty - fuel line and carb are now 'dry'
3) Disconnect plug wire from plug
4) Empty fuel tank into suitable container
5) Dump bottle of Seafoam into fuel tank and pump up into fuel line and press primer bulb until you know carb is now full of Seafoam
6) Slowly pull starter cord so Seafoam gets thru and past carb into inlet manifold and cylinders

Let sit overnight

7) Next day, drain fuel line by removing piece before primer bulb and put that Seafoam into the tank
8) Refill your tank with the fuel mix you put aside
9) Drain carb bowl to empty all Seafoam (discard this - it's full of crud) - leave drain screw out for step 10
10) Remove plug and slowly crank through, getting ALL Seafoam out of the motor
11) Re-install plug, drain, screw, and hook it all back up and start 'er up!

FYI, I bypass steps 4 & 5 by disconnecting the fuel line under the OB cowling and using an injection syringe to fill the carb full of Seafoam.

If you want to be extra sure, for step 8, only put back in < 1-gallon with the rest (most of it!) of the Seafoam mixed in. Run the motor @ high idle and shut off for 15-minutes. Repeat. Repeat. If she smokes like a banshee, that's carbon you're buring off the rings, piston, and cylinder walls.

Remember - Seafoam 'works' when the motor is sitting off ... not whilst running .

 

[jeffnick]

Lazy man's way is to turn off gas, take out plug to drain carb and using a syringe fill bowl w/ carb cleaner via overflow hose or drain plug hole. Let sit overnight. Drain again. Put in plug, turn on gas and away you go.

 

[MacFern]

THANKS - GREAT INSTRUCTIONS

 

[MacFern]

I just got home and took a look at the motor, and I guess I was picturing something different. I thought I'd be able to see some type of screw or plug that could easily be removed to empty the drain bowl - I don't see it. Do I need to take the carburetor out to do this?

 

[MacFern]

OK, followed Dales Seafoam process, ran a little better so I followed the whole process a 2nd time. Now it's running a lot better but still won't idle or run continuously without using the choke. I am at the point of removing and using the carb cleaner kit from the auto parts store, but I'm also thinking if I just keep doing this Seafoam process maybe it will continue to improve - or will it only do so much, and in the end still need the full carb cleaning process? Just trying to save $20, a trip to the store, and taking apart anything I don't have to.

I also have a question about step #10 " Remove plug and slowly crank through, getting ALL Seafoam out of the motor". Should I be able to see anything coming out of where the plugs go? I don't, and so I was thinking maybe I'm not getting enough Seafoam into the carb/motor.

Also, I have a can of carburetor cleaner I bought a while back that you spray into the carburetor while the motors running. Any chance this stuff may work better than the Seafoam. I want to try it but don’t want to cause more damage than good.

 

[MacFern]

Well I did the Seafoam process 2.5 times (3rd time I only let it sit a half day), and then I did the more thorough carb cleaning process where the carburetor is immersed in the cleaning solution for 20+- minutes. The motor still won’t run without either constantly revving the throttle or using the choke. I'm dissapointed that this didn't work, but I am glad I got to mess around with the engine a little - had no idea how simple the carburater was, and how easy to remove.

Any other advice before it goes to the shop?

 

[DaleH]

To me, on small OBs, if the SEafoam doesn't do it ... the immersion will. Let me check with my friend (PhD Chemist) , as maybe you can soak it longer. Hold on ... uhhhh, but you immersed with needle valve out, right? FOrcing stufff in there too with a syringe???

 

[MacFern]

Yes, took out needle valve. as for syringe - it was more like a turkey baster (all I had). But I also spayed it with some carb cleaner from a can. The cleaner I used said no plastic/rubber so I took off the float, any plastic, and the little black box the fuel line connects to before soaking it. I don't have an air compressor, so after rinsing with water (per instructions) I dunked it in clean gas.

 

[DaleH]

On some the tip of the float shutoff is a phenolic or rubber. I tell you, you practically cannot screw up a small OB carb. I take them apart, assembling parts in order as I pull them off, (taking digital pics now w/ camera), and clean it all out, as gunk sometimes sits in corners. Just be careful with any gaskets. Flushing from small orifice to larger ones, poking spring or guitar wires in where I can't 'see'.

 

[jeffnick]

As Dale suggests, there are some VERY small orifices in the carb, and getting them open is the key. I've never done your Yammy, but my Honda had some openings so small that nothing would work execpt compressed air to get them open (after a carb cleaner soak).

 

[MacFern]

Ok thanks, guess I'll buy a compressor and try again. I'd rather do that then pay the dealer to fix it. Any type of small compressor good for this, I figure I'll get something I can at least use to fill trailer/vehicle tires.

 

[MacFern]

Ok thanks, guess I'll buy a compressor and try again. I'd rather do that then pay the dealer to fix it. Any type of small compressor good for this, I figure I'll get something I can at least use to fill trailer/vehicle tires.

 

[DaleH]

Ok thanks, guess I'll buy a compressor and try again. I'd rather do that then pay the dealer to fix it. Any type of small compressor good for this, I figure I'll get something I can at least use to fill trailer/vehicle tires.

I used to use small comp air cans, then got a good quality portable 12V compressor for the car (& boat trailer) and modified a typical 'basketball' or inflatable nozzle tip by cutting off the end and turning it to a sharp point in a lathe [or drilll with a file ]. Works for me, plus I get the use of the pump for emergencies or to keep auto/trailers topped up with air whilst on the road .

 

[MacFern]

Thanks Dale - good idea and auto Zone has one 50% off!!

 

[DaleH]

As Jeffnick said ... there are small orifices in some carbs, like those in Hondas are as small as a human hair.

That's how they squeeze the HP out of the small blocks ... or those heavy 4-strokes would be even heavier :shock: ! .