Carburettor cleaning- what's best?

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sparkie

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Hi all, been having recurrent problems with the Tohatsu 6 this season, all centered on fuel. I've completely dismantled and cleaned the carb and jets N times as well as I can, including soaking it in thinners and acetone overnight, but I still think there must be a small conduit/passage/airway that's gummed up or obstructed. Is there anything else I can soak it in that would dissolve any remaining muck? Is this ultrasound cleaning any good? My next step is a new carb, but I'm going to give the existing one more go over the winter.

Next step if the new carb doesn't work the Tohatsu will be converted into an anchor......
 
Oddly enough I have a Mariner 6 which I think is the same engine, and also have been having fuel issues. I have just dropped it off to have the carb ultrasonically cleaned among other things. I'll get it back next week and let you know.
 
Do you know anyone with a compressor who could blow high pressure air through all your orifices?
I presume you've already checked the supply pipes and tank for blockages, but shoving air up your pipe may also help. Empty tank first of course and put that fag out.
 
Just possible it may not be fuel.

I have a Tohatsu 3.5 that was giving me all the symptoms of fuel starvation - running OK at low power, but misfiring and eventually dying when asked to provide a bit of go.

I stripped the carb several times to no avail before a sharp-eared mate noticed an intermittent ticking sound, which turned out to be the coil sparking to earth. The connection of the coil earth lead to the engine body was corroded and the spark that looked good with the plug out wasn't so good when it mattered.

A clean of the connector and the bolt and it was fine.
 
PeteCooper said:
Oddly enough I have a Mariner 6 which I think is the same engine, and also have been having fuel issues. I have just dropped it off to have the carb ultrasonically cleaned among other things. I'll get it back next week and let you know.
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V.interesting. There are three other Tohatsu/Mariner owners in the same harbour as me having similar issues. All with engines approx 6-7 years old. I've thought for a while that there is a common problem here which we're not getting to the bottom of.

Be v.useful to hear the results of your ultrasonic clean, so keep us posted.

Cheers.
 
Floyd Raser said:
Do you know anyone with a compressor who could blow high pressure air through all your orifices?
I presume you've already checked the supply pipes and tank for blockages, but shoving air up your pipe may also help. Empty tank first of course and put that fag out.
Click to expand...

Yes I do have a friend with a compressor, and it would be worth trying I'm sure. Not certain whether it would clear any gum though... Yes plenty of fuel getting to the carb, so don't think that's the problem. Cheers.
 
Stemar said:
Just possible it may not be fuel.

I have a Tohatsu 3.5 that was giving me all the symptoms of fuel starvation - running OK at low power, but misfiring and eventually dying when asked to provide a bit of go.

I stripped the carb several times to no avail before a sharp-eared mate noticed an intermittent ticking sound, which turned out to be the coil sparking to earth. The connection of the coil earth lead to the engine body was corroded and the spark that looked good with the plug out wasn't so good when it mattered.

A clean of the connector and the bolt and it was fine.
Click to expand...

That's v.interesting, I've tried a new plug, of course, but no different. However, not thought of any other ignition problems as it seems to be fuel. I'll definitely check out that connection next time I'm down there. Cheers.
 
sparkie said:
Is there anything else I can soak it in that would dissolve any remaining muck?
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(Many other brands are available.)
 
sparkie said:
Cheers- is this added to the fuel??
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No - it's a solvent you use to clean the thing with. Supposed to be good for the varnish-y deposits which can gum up narrow passageways. I've not used, it, though, so it may just be a mixture of white spirit and snake oil. Could be worth a go, though.
 
+1 for carb cleaner. Got mine at Halfords I think. After a season of poor running, I found all sorts of gunk and goo was loosened by this stuff. As it's aerosol, it gets into the fine bits too. I now use a petrol additive to improve life of fuel - again Halfords I think.
 
wallacebob said:
+1 for carb cleaner. Got mine at Halfords I think. After a season of poor running, I found all sorts of gunk and goo was loosened by this stuff. As it's aerosol, it gets into the fine bits too. I now use a petrol additive to improve life of fuel - again Halfords I think.
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Seems like a good idea, especially the aerosol package- I can see that maybe working with a fine tube. Well worth a try anyway. Cheers.
 
Ultra sonic cleaning is excellent and part of the answer. Wife's Christmas present perhaps, as it is great for jewellery. sub 60 note for a good one on e bay.

The other part is the 5% ethanol in regular petrol these days.

Try BP premium as at the moment has no alcohol. It certainly helped this yearwith a 8hp yamaha 4 stroke we have, along with a lesser pitched prop.
 
I had a tiny honda moped cleaned ultrasonic ally after all my other usual methods failed, carb cleaner, acetone, petrol, poking fuse wire about etc, it was the only thing that worked for me. Good luck with it.
 
JumbleDuck said:
No - it's a solvent you use to clean the thing with. Supposed to be good for the varnish-y deposits which can gum up narrow passageways. I've not used, it, though, so it may just be a mixture of white spirit and snake oil. Could be worth a go, though.
Click to expand...

I've used one from Euro Car Spares to good effect. A few £.
 
JumbleDuck said:
No - it's a solvent you use to clean the thing with. Supposed to be good for the varnish-y deposits which can gum up narrow passageways. I've not used, it, though, so it may just be a mixture of white spirit and snake oil. Could be worth a go, though.
Click to expand...

VicMallows said:
According to the COSHH data sheet, the TECTANE brand version that ToolStation sell is a blend of Xylene/Ethanol/Acetone.
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Several I looked at were similar. viz toluene, methanol and acetone.

(I'd avoid anything with snake oil in it ! ;) i reckon that could block small orifices etc. )

Also be aware of the possible incompatibility of these solvent mixtures with plastic parts !
 
sparkie said:
Seems like a good idea, especially the aerosol package- I can see that maybe working with a fine tube. Well worth a try anyway. Cheers.
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I have a recalcitrant Citroen DS carb which needs some TLC, so I'll try some too. Webers have a horrible number of passageways and jets ...

david_bagshaw said:
Ultra sonic cleaning is excellent and part of the answer. Wife's Christmas present perhaps, as it is great for jewellery. sub 60 note for a good one on e bay.
Click to expand...

Lidl have them fairly regularly.
 
Has anybody tried one of these glass sparkplugs 'colourtune' that we used to use 20 years ago?
It seems to me that there is a preponderance of owners with the same (or similar) problems and I've seen a lot of dosh being spent to no avail
Something is WRONG...
PS I don't have one, but I know someone who does.
 
Billjratt said:
Has anybody tried one of these glass sparkplugs 'colourtune' that we used to use 20 years ago?
It seems to me that there is a preponderance of owners with the same (or similar) problems and I've seen a lot of dosh being spent to no avail
Something is WRONG...
PS I don't have one, but I know someone who does.
Click to expand...

Yes. These are only used to set the mixture though.
 
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