Tohatsu 4hp 4 stroke 2008 modle

robert53a

Petty Officer 2nd Class
Joined
Dec 27, 2007
Messages
181
Hi I just bought this little motor and did the usual maintenance to it. I was running it in the barrel and had a hard time keeping it running at low idle. I went for the adjustment screw and found the the plastic lobe that hold the the adjustment screw and spring was broken off. Tried to find that part in the part catalog and to make this a short as possible, ended up buying a new carburetor. Does anyone know if they sell just the plastic bell crank by itself? Thanks ......Robert
 

pvanv

Admiral
Joined
Apr 20, 2008
Messages
6,500
What is your actual model (year is irrelevant)? Assuming you have an MFS4B. There is no plastic limiter on the idle stop screw. It's just a stainless coil spring to keep the screw from drifting once set. The pilot mixture screw is inside a brass block-out plug. BTW, the carbs for the MFS4,5, and 6 interchange, so if needing a new carb, always get the one for the MFS6A. More power, and better idle.
 

robert53a

Petty Officer 2nd Class
Joined
Dec 27, 2007
Messages
181
Hi, thanks for the response. The model number is MFS4BD. Hi Im talking about the idle adjustment. the screw and spring are gone because the plastic bell crank is broken off that house those components. The carburetor I ordered is for an a model.
 

km1125

Chief Petty Officer
Joined
Aug 10, 2016
Messages
496
Well, hopefully you bought the 6HP carb, as Paul was mentioning they are interchangable and you'd have 50% more power!!

I have an older carb that's no good and still has a good bell crank with the screw and spring. If you want I can take it off and send it to you.
 

km1125

Chief Petty Officer
Joined
Aug 10, 2016
Messages
496
I pulled it out of the old carb.

You need to pull the screws out of the 'butterfly' and remove the butterfly. Then remove the screw on top that holds the bracket just under the spring. You can then slide the old belcrank assembly up and out of the carb.

When you put the replacement in, reverse the procedure. However, before you put the butterfly screws in, you could use some threadlock on them (the originals were staked on the backside, which you can do too, but it's more work). BEFORE you tighten the butterfly screws all the way, back off the idle speed screw entirely so the butterfly fully closes and make sure the butterfly is perfectly centered before you tighten the screws the rest of the way. Then you can put a couple of turns back in the idle speed screw to give just a tiny opening. You'll have to fine tune the idle speed after you get the motor running.

Respond to my PM for shipping info.

belcrank.jpg
 

robert53a

Petty Officer 2nd Class
Joined
Dec 27, 2007
Messages
181
Got the old one removed and thought I'd try to post a picture. Not very good, I'm afraid.
 

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km1125

Chief Petty Officer
Joined
Aug 10, 2016
Messages
496
The replacement parts should be there on the 18th, if USPS holds to their "word".
 

robert53a

Petty Officer 2nd Class
Joined
Dec 27, 2007
Messages
181
Replacement parts installed and motor checked good idles nice now. Thanks everyone.
 

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