Removing carb from Tohatsu MFS 20C

[ghmerrill]

I need to pull the carb off this motor of mine to clean it. Seems pretty straightforward, but I can't see how to get a wrench on one of the bolts. There are two long bolts that go through the base of the plastic air intake and then through the carb body. The outer one is easily accessible. There isn't enough room to get a socket on the inner one from the front, and I don't see how to get something like a box wrench on it from the side.

How am I supposed to get this carb off? Thanks for any insight.

 

[ghmerrill]

Just talked to a mechanic where I got the motor some years ago. I don't want to mess with what it will take to get that carb off. Going to take it in for a rebuild probably within the next week when he gets the kit. At least it's good to know that I wasn't missing anything obvious about removing the carb.

 

[pvanv]

To get that carb off, pull the intake with the carb attached, then remove the carb.

 

[ghmerrill]

To get that carb off, pull the intake with the carb attached, then remove the carb.

Yeah, so I was told. But I don't think I want to mess with that -- at least this time around. I also don't have any specific instructions for what "pull the intake with the carb attached" means, and I don't have any diagrams of precisely what to do. Sure, I can probably figure that out; but after talking to the mechanic and getting their likely turn around time -- and that he can have a full rebuild kit for it within a week -- I decided just to take it to him and let him do it. These are the people I bought it from, and I like to throw them business when I can anyway.

But I do have one question you might answer ...

So I know this problem was totally my fault, but I'm unsure how to avoid it in the future. At the end of the boating year, just before COVID struck, I did the usual "winterizing" of the motor which included draining the fuel line and the carb to the best of my ability without disassembly. That's always worked in the past, but this time the boat sat for two years without use, and I can't really blame the carb for gunking up with some minor residue over that time. But then the question is "How could I have avoided that?" What more was there to do? Run the motor to use any possible remaining fuel in the float bowl or internals? Would THAT have avoided the problem? Manage to spray something like Sea Foam into it as it's running? Pull the carb off and thoroughly clean it and blow it out? What would it take?

I have several 2-cycle engines around there that didn't end up gunking up over that time, and a 4-cycle log splitter engine that had no problem. But none of them sat unused as long as the Tohatsu 20 did.

 

[pvanv]

If acarbed outboard will sit for more than a day or 2, I always run the carb dry. If you leave fuel in it for a week or 2, you are asking for gunk. You can drain the bowl if you forgot to run it dry. Pulling the intake only involves a few 6mm bolts with 10mm heads and it pops right off. Sometimes you can even re-use the intake gasket. I seldom if ever need a kit; just a good heated ultrasonic bath for about 6 hours, and then a liberal blow-out with carb spray fixes 99% of them.

 

[ghmerrill]

If acarbed outboard will sit for more than a day or 2, I always run the carb dry. If you leave fuel in it for a week or 2, you are asking for gunk. You can drain the bowl if you forgot to run it dry. Pulling the intake only involves a few 6mm bolts with 10mm heads and it pops right off. Sometimes you can even re-use the intake gasket. I seldom if ever need a kit; just a good heated ultrasonic bath for about 6 hours, and then a liberal blow-out with carb spray fixes 99% of them.

Yeah, I've become much more careful with my small engines in my old age, and it's like magic -- if you don't let them sit with fuel in them, then they'll start for you!! Who would have thought? Took me a couple of decades to learn my lesson.

I just took a look at the boat motor and I see those 10mm bolt heads -- looks like 6 of them. So I will definitely do that the next time -- in fact should probably do it pro-actively and for practice when I put the boat up next winter. So thanks much for that.

Do you know of any source for a service manual for these motors? The Tohatsu one seems to be unavailable. Or any online versions of it? Or something that would be close enough for that? I don't mind paying a mechanic for repairs, but I do like to do what I can by myself -- or at least figure out what probably needs to be done. Thanks for any info.

 

[Sea Rider]

If a carbed outboard will sit for more than a day or 2, I always run the carb dry. If you leave fuel in it for a week or 2, you are asking for gunk.

Right specially if it's a 2 stroke motor, to play safe I always run my carbs dry soon after returning to dryland, that's while flushing the motor geared at fast idle on muffs, gives a nice 5 minute water flush before the carbs runs dry and shuts the motor Off.

With this method ever in my life have I needed to install a complete carb kit, all internal metal parts and jets are 100% cleanable, as a preventive maintenance have changed only the fuel pump's diaphragms which were ballooned by E blended fuels in current use...

Happy Boating​

 

[ghmerrill]

Right specially if it's a 2 stroke motor, to play safe I always run my carbs dry soon after returning to dryland, that's while flushing the motor geared at fast idle on muffs, gives a nice 5 minute water flush before the carbs runs dry and shuts the motor Off.​

I do that with my 2-cycle small engines. And for our (4-cycle) log splitter I do it if I know it's going to sit for more than a couple of weeks. But I think I do need to be doing it with the (4-cycle) boat motor since our schedule for using it is so sporadic. It's not a big deal and takes only a few minutes.

 

[Sea Rider]

I do that with my 2-cycle small engines. And for our (4-cycle) log splitter I do it if I know it's going to sit for more than a couple of weeks. But I think I do need to be doing it with the (4-cycle) boat motor since our schedule for using it is so sporadic. It's not a big deal and takes only a few minutes.

Don't have any personal experience whatsoever in whether straight fuel run in carbs will gunk or not any carb if sitting for too long, but if boating in salt water it's the perfect excuse to run the carb dry while flushing the motor with fresh water soon after returning to dryland. Other point to consider, although you can schedule in advance your next boating day anything can happen in the interin and far extend the days beyond what was initially scheduled for, if that happens the motor will sit sweet with carb(s) dry.

During the C-19 Pandemia and due to an extremely unwanted long stop, all the motors living at my Boating Club were found with highly gunked carbs which took long hours to clean. Being a cautious boater my motors were the sole exceptions to this awful escenario...LOL!!

Happy Boating
​

 

[ghmerrill]

During the C-19 Pandemia and due to an extremely unwanted long stop, all the motors living at my Boating Club were found with highly gunked carbs which took long hours to clean.​

Thanks. That makes me feel a little less stupid. It's exactly what happened in my case.

 

[Sea Rider]

Thanks. That makes me feel a little less stupid. It's exactly what happened in my case.

Well, you always learn new things not mentioned in any Owner's Manual, it's basically a word of mouth thing. Now that you have experienced so won't go that route again. LOL!!

Happy Boating​

 

[ghmerrill]

Knowing what to do (or what you should do) and doing it are two different things. Plato thought that "To know the good is to do the good." But he was wrong.