tohatsu 5hp 2-stroke not idling

[BoatingTimbo]

i've never seen an outboard this hard to keep tuned carb clean enough to have it idle!

is everyone with this outboard having the same problems?

I have just fully disassembled the carb, cleaned, soaked and put back together to the exact same problem. Can't adjust idle to keep it idling at all!

Should i just put rebuild it with the rebuilt kits you can get? Any advice would be good.

Thanks.

 

[pvanv]

Re: tohatsu 5hp 2-stroke not idling

Did you install a kit in the carb? Is the fuel pump working well? Is the float height correct? Is there any distortion to the viton tip of the needle? How many turns is the pilot screw set to? Is the compression good? What does the plug look like? What idle RPM are you trying to achieve? Does it run well above idle? If everything in the carb looks OK, and the motor does everything else well, but just won't idle, there is probably still an issue with the low-speed circuits (air, fuel, or both) in the carb.

 

[TOHATSU GURU]

Re: tohatsu 5hp 2-stroke not idling

Small outboard equals small jets. What kind of carb cleaner are you using?

 

[BoatingTimbo]

Re: tohatsu 5hp 2-stroke not idling

I'm using a spray can that i sprayed all parts and through the jets then soaked (with the remainder of the fluid from the spray can) for a almost 3 hours. I didn't install carb kit but think i might. The main nozzle jet i was unable to get out but unscrewed the main nozzle from the top of it. The slow jet i sprayed and soaked and inspected and looked fine. When i pulled the carb apart it was spotless. The guy i bought it from said in it's spring service (only one running ago) it had a carb cleaning.

I guess i'll try taking apart and soaking overnight and if that doesn't work i'll get a carb kit?

runs perfectly fine with no issues... just struggles to idle

 

[TOHATSU GURU]

Re: tohatsu 5hp 2-stroke not idling

Mechanic in a Can is no substitute for carb cleaner. You need to get on your unicycle and get to an auto parts store and buy a one gallon can of carburetor cleaner. The spray stuff isn't a real cleaner, it's a metal brightener. The difference is the acid value. The stuff in the gallon can will actually dissolve the deposits that you cannot see, deep down in the carb passages and inside the hidden jet.

 

[BoatingTimbo]

Re: tohatsu 5hp 2-stroke not idling

What a good excuse to get on my unicycle! thanks for that advise. I thought they were same fluid, just pressure vs. fluid. I'll do that and soak overnight. Hope that helps!

 

[pvanv]

Re: tohatsu 5hp 2-stroke not idling

Be Careful. Use a real carb dip, such as Tyme. Soak for 4 hours at room temperature. If you soak it less, it may not be effective enough. Soak it longer, and you may start etching the aluminum of the carb body. So don't soak "overnight", unless you have very short nights

 

[BoatingTimbo]

Re: tohatsu 5hp 2-stroke not idling

got a heavy duty carb soak and soaking right now. Took apart another old outboard carb to do at the same time as well. found a small piece of wire to pock through the idle jet and it was infact blocked. Thanks for the help, will let you know how she turns out.

Can you re-use this carb cleaner? The carb was/is spotless but once it's used once is it no good anymore? Would rather recycle it to use again or on the next carb rather then try and figure out where to take it for disposal???

 

[TOHATSU GURU]

Re: tohatsu 5hp 2-stroke not idling

It's reusable. It's also hydroscopic so keep a tight lid on it.

 

[pvanv]

Re: tohatsu 5hp 2-stroke not idling

Don't go poking wires through the passages. That can cause micro scratching, which can lead to very weird fuel flows.

 

[BoatingTimbo]

Re: tohatsu 5hp 2-stroke not idling

tested tonight in water, got idle set perfectly not under load but having some problems setting the idle screw to run right. I started with 1.5 turns out tested to get to WOT and it's bogging down. whats the proper way to set the idle screw? Thanks for the continued help.

 

[pvanv]

Re: tohatsu 5hp 2-stroke not idling

The pilot screw has little, if any, effect at WOT. Adjustment info is in the Factory service manual. The pilot is for adjusting idle mixture. Start about 1-1/2 to 2 turns out, and after fully warmed and equipped with a good shop tach, adjust for highest idle. then readjust idle stop screw to stay in specs and repeat the pilot adjustment. Then repeat again. Requires a good ear. When you have the max idle from the pilot, richen it about 1/8 turn for stability on deceleration.

 

[BoatingTimbo]

Re: tohatsu 5hp 2-stroke not idling

sorry guys to bug you all again... i'm hoping to give it one last chance fixing myself then will break down and take to the shop!

I have adjusted the pilot screw the suggested way, motor idles perfectly but when hitting WOT it's bogging down and won't fully rev up. At full out i pull the choke a fraction of an inch out and it starts reving better and speeds to get to plane. Is this a clue i don't have the pilot screw set properly? What do you think?

 

[pvanv]

Re: tohatsu 5hp 2-stroke not idling

You are too lean at WOT. Is the float height correct?

 

[BoatingTimbo]

Re: tohatsu 5hp 2-stroke not idling

i've kept cranking the screw out to richer assuming it was running to lean but no real change. Didn't think to check float height. When i put back together it didn't look like there was any way to adjust float height? Could it be fuel flow issue. When i put the fuel pump back on the carb could i have i have put the diaphragms back in wrong? Only looked like there was one way they installed back in. I also pulled the tank apart and cleaned the fuel filter.

 

[pvanv]

Re: tohatsu 5hp 2-stroke not idling

Info on setting the float height is in the factory service manual. The pilot screw does not affect WOT mixture.

 

[Paulgilby]

Re: tohatsu 5hp 2-stroke not idling

Info on setting the float height is in the factory service manual. The pilot screw does not affect WOT mixture.

QUOTE]

BoatingTimbo,
Have you resolved your problem completely?
I experienced a similar issue these past days. First, i left the engine around 2 months without use and when I tried to start it i found that the mixture was browned and oil clogged in the fuel tank. I cleaned up the tank and refueled the tank, but used some of the same oil. It started well and at high rpm worked well, but dropped at low rpm and idling. Then I moved to clean the whole carb in carb cleaner soaking it for 20 min, deassembled but the idling issue was still there. After that I removed the carb and cleaned the slow jet and the main jet as well and soaked back, but this time in thinner. In the process the fuel pump seals got white, looking as dried out so I changed and also changed some rubber seals that attaked by the carb cleaner. Yesterday, tried again and the starting was smoother, but still didn't idle. I then removed the idling screw and cleaned it and after that it starting idling. Seemed to be working fine, but dropped in some ocassions when idling and when throttling from idle. My next step is to try a new mixture of fuel and with a newer oil.
What do you guys reckon this could be? Some further carb cleaning? What is the white powderish substance on slow and main jets?
Thanks,
Paul

 

[pvanv]

Re: tohatsu 5hp 2-stroke not idling

First off, don't try to revive a year-old thread; start a new one.

But...

Do a complete disassembly, including jets and emulsion tube nozzle, use real carb dip, and do a real 4-hour soak at room temperature, followed by a blow-out with generic spray, followed by a careful reassebly.

Otherwise, you have not cleaned the carb. Period.