Carb float setting for Tohatsu 5 hp

[chuck in WA]

Hi gents,
I want to rebuild the carb on my Tohatsu M5B because it's been slowly leaking fuel out of the carb after shutdown. I ordered the rebuild kit (thanks Iboats!), but when it arrived I was disappointed to find that there was no documentation indicating the correct float setting (or documentation of any kind for that matter). I don't have any kind of manual whatsoever for the motor. Can anybody point me in the right direction for the proper float setting and where the measurements are taken?

Also, is there a way to find out what year the motor was built? The ID plate lists 369 73287.

One last thing - is there an owners manual available somewhere on the interweb for download? It would be nice to have.

Thanks all!

 

[pvanv]

Re: Carb float setting for Tohatsu 5 hp

Year is unimportant for servicing a Tohatsu OB. Precise model/serial is everything. If you have a nostalgic curiosity about the date of manufacture, you could call Tohatsu at 214-420-6440 and ask... they might be able to look it up.

Not sure which kit you ordered... The correct kit includes gaskets, float & needle valve, Fits: 5B, 8B & 9.8B 2-stroke models. Tohatsu/Nissan Part# 369871221M. No, it does not come with instructions... after all, it's a service part, not a manual. The float height should be set so that the float is parallel to the carb casting when the carb is inverted.

The Factory service manual, available from any dealer (including me) is Part# 003-21035-1 $44.17. I have them in stock. Don't bother with the aftermarket manuals.

Your owner's manual can be downloaded from http://www.tohatsu.com/tech_info/manuals.html

 

[chuck in WA]

Re: Carb float setting for Tohatsu 5 hp

Thanks very much Paul. So I'll assume that there isn't a specification for float drop in this application? I only ask because I recently rebuilt my Mercruiser carb which had a spec. for both high and low float levels. Thanks again.

 

[TOHATSU GURU]

Re: Carb float setting for Tohatsu 5 hp

"The float height should be set so that the float is parallel to the carb casting when the carb is"

The only spec that you need. This is a stone hammer type of engine.

 

[pvanv]

Re: Carb float setting for Tohatsu 5 hp

Right. As Elvin noted, on this motor, the shutoff point (float height) is all that matters. The fuel delivery is so robust that float drop is unimportant -- the carb bowl is almost always completely full when running.

 

[chuck in WA]

Re: Carb float setting for Tohatsu 5 hp

Thanks again for the info gents. Carb rebuild is now complete - she starts on first pull and purrs like a kitten!

Not peee'ing very much in the test tank now though, when I previously (last year) had a good stream....hmmmm....

 

[pvanv]

Re: Carb float setting for Tohatsu 5 hp

You can check for debris in the pee tube by pushing a still wire or fishing line into it while the motor is running (in water, of course). Sometimes salt or other junk will stop up the pee tube.

 

[chuck in WA]

Re: Carb float setting for Tohatsu 5 hp

Thanks PV - couple shots of compressed air and it's peeing like me after a 6 pack again now!