Tohatsu 9.8 Outboard Carburetor - slow running jet removal

[Jaguar 25]

I sem to have a problem with a partially blocked slow running jet on my 2010 Tohatsu outboard carb. Does anyone know if this jet can be removed whilst leaving the carb in-situ or do I need to remove the carb?

If carb removal is required (which I think is necessary) do I need a new gasket when refitting it.

Appreciate any advice that can be given.

 

[VicS]

Personally i would much prefer to remove the carb to the workbench unless there is a good reason not too and it is easy to remove the float chamber and other small parts in situ.

There are two gaskets and an insulating spacer between the carb and the manifold. With luck you will be able to remove the carb without damaging the gaskets.
Like wise the gasket between the float chamber and the carb body.

Sods law applies... Order new gaskets and you won't need them. Dont bother and you will!

 

[Jamesuk]

I sem to have a problem with a partially blocked slow running jet on my 2010 Tohatsu outboard carb. Does anyone know if this jet can be removed whilst leaving the carb in-situ or do I need to remove the carb?

If carb removal is required (which I think is necessary) do I need a new gasket when refitting it.

Appreciate any advice that can be given.

We had an 8hp with the same problem, take it all apart buy if you dont have one already an air compressor shoot it full of air clearing it all up and any water might be in there, no gasket required but nice if you have one and it should be just right when you start it up. Or jus hammer it hard for a 30 min period

 

[seanfoster]

The best way to clean carbs thoroughly is with an ultrasonic cleaner, I bought a 2.5L one on ebay for £60, not sure whether it's worth it to buy one for just one job, but you can put it to use for lots of other tasks. You would need to remove the carb obviously!

 

[Lakesailor]

Echo the thoughts. Remove carb. Use new screwdriver with large enough blade to fill the slot. They are only brass and can easily damage. Blow through if possible to clean the jets and passageways.

Tohatsu have a habit of using brass spacer rings to nip the carb up around the securing bolts where they pass through the fibre block between the carb and air intake. These rings can easily fall out when you are removing the carb. (if you have the parts diagram it's 10/13 or the alternative 12)

"Plop"

I tend to hang a bucket or similar beneath the motor to catch any bits that drop off if working on the motor on the stern.

 

[Iliade]

I have the same engine and repeatedly suffer the same problem.

Remove & strip carb and ultrasonic clean it.

Blow it out with compressor.

Do likewise with the pump on the back of the motor.

...and the hoses.

Fit an additional in-line filter just ahead of the carb.

Replace with new gasket.

Repeat after three months... :0(


Get you home tip: remove shiny plate from top of carb & blast carb cleaner down all the visible holes, one of them is the offending jet, but this is unlikely to be the only bit of muck in the system.

 

[Jaguar 25]

Thanks SAPurdie - some clarification please.

Not sure what "ultrasonic clean it" is means. Sounds like I need some kit to ultrasonically vibrate the carb in a bath of some sort?

Presume that "Replace with new gasket" means the gaskets between the upper carb body and the float chamber. Is this true and additionally, how about the gasket between the carb and the intake manifold - does need to be renewed on reassembly?

Also, I can only see an American source t=for the parts. Is there somewhere in the Uk that I can order them from?

"Repeat after three months... :0(" Seems painful!


Get you home tip: remove shiny plate from top of carb & blast carb cleaner down all the visible holes, one of them is the offending jet, but this is unlikely to be the only bit of muck in the system.[/QUOTE] I have tried using carb cleaner through what I see as the inlet filter but is described in the parts list as a silencer. This has helped a little and hopefully, there is no paper filter element in there that I have clogged up.

 

[Lakesailor]

Ultrasonic cleaners are a bit OTT for a carb clean unless it is really gummed up. You be as well finding someone who has a commercially sized one and getting it done for a fee.

Carb cleaner is of little use as a spray. You really need to soak the carb in it for a day.

If you get recurring problems change the inline filter and change your fuel can. Once the carb is properly clean it shouldn't be difficult to keep the new fuel clean.

Rib Shop for parts http://www.rib-shop.com/prodtype.asp?cookiecheck=yes&PT_ID=176

 

[Iliade]

Not sure what "ultrasonic clean it" is means. Sounds like I need some kit to ultrasonically vibrate the carb in a bath of some sort?

Yes. if water has got in it'll have allowed surface corrosion/debris to build up in all the little cavities. The only reliable way of dealing with this is an ultrasonic bath. Soaking in carb cleaner prior to the bath will help remove any lacquer or gum deposits, but these motors are barely old enough to have accrued that. You need mechanical action to loosen the scaling etc. Carb cleaner is not kind to plastic components. The pump is also a source of corrosion products which will block the jets. A filter twixt pump and carb is a good idea. Unfortunately modern 'petrol' seems to be rubbish with water.

Presume that "Replace with new gasket" means the gaskets between the upper carb body and the float chamber. Is this true and additionally, how about the gasket between the carb and the intake manifold - does need to be renewed on reassembly?

The float body gasket can often be reused (at your own risk) but the manifold gasket is more critical. A minute air leak and the motor will not idle.

Also, I can only see an American source t=for the parts. Is there somewhere in the Uk that I can order them from?

I used gasket paper, from any good motor factor, as I didn't have the time to get from a UK dealer, of which there are many - google them.

"Repeat after three months... :0(" Seems painful!

Quite! These carbs are notorious for this. Check out various other forums for similar sob stories.

Get you home tip: remove shiny plate from top of carb & blast carb cleaner down all the visible holes, one of them is the offending jet, but this is unlikely to be the only bit of muck in the system. - I have tried using carb cleaner through what I see as the inlet filter but is described in the parts list as a silencer. This has helped a little and hopefully, there is no paper filter element in there that I have clogged up.

Putting cleaner in the carb inlet will do nothing beneficial, despite anything to that effect written on the can. You need to clear the obstruction in the jet, which is accessible from the top plate of the carb. Don't use wire to clear the jet as you could damage it or break the wire off in it. An airline would do just as well, but not so easy to row out to the mooring. 'Canned Air' is not usually massive enough or at high enough pressure to suffice. Nearly any spray cleaner would probably suffice, but spray carb cleaner is designed for the job...

If you can get it to start, running at high revs, blocking the inlet then shutting the throttle can sometimes shift the blockage, but don't blame me if fingers and thumbs go flying about the boatyard...

 

[Jaguar 25]

Thanks for the responses and explanations. I have now ordered a double set of the gaskets plus a new slow running jet (thinking it would be cheap but no £23!) .

Still can't understand (speaking as a mechanical design engineer) why anyone would design a carb without including easy access to the slow running jet for removal without needing to disassemble the carb as most car carbs had (when they had carbs!).

 

[mvalle]

I clean my carb about every two to three months depending on use, What I cant find is their any adjustment to the jet. I have it screwed down until it stops.