I remember reading some years ago you could get a little hand-held pump that you could set to either vacuum or add pressure. Someone used one in these forums I think for testing carbs, you could set it to vacuum and apply negative pressure to see if a needle was seating correctly, or apply pressure, but I can't remember what it was called or where to get them. I did find it though some years ago. The only thing I can see is a vacuum pump (for brake bleeding) as seen here, which iirc looked similar to this design but it seems this one only does vacuum.
[EDIT] Just came across this one though $140 is a bit steep. Anyone know of a cheaper option?
The MityVac is the one I have here. And I had no problems with it. I use it mainly to pressure/vac test 2 cycle crankcases but I also do test carburetors with it. And being able to do both pressure and vac testing is necessity here.
At least is rebuild-able if ever needed.
I paid no where near the current US price but it also been 10+yrs since I brought it.
Sorry for the delay in reposting, appreciate the comments
Originally Posted by AVB
The MityVac is the one I have here. And I had no problems with it. I use it mainly to pressure/vac test 2 cycle crankcases but I also do test carburetors with it. And being able to do both pressure and vac testing is necessity here.
How often do you Vac test ?
Originally Posted by Mowerfreak
Is it metal or plastic?
Both ABS and metal. Looks like it only does vacuum though .
Originally Posted by NormK
Hi Widget, I could never see how you could justify the expense for the amount of work you do
Originally Posted by Mowerfreak
I agree, way to specialised. I would just run cleaner through it and perhaps a kit.
True, though in my (lack of) experience, I've never really been successful in repairs. Have got a couple things started, but have spent more times troubleshooting and pulling things apart than fixing. I figure having a little pressure tester might help with that. I have a repair kit for my ECHO trimmer carb that I'm putting together, someone suggested to pressure test to ensure the needle seats good and there's no leaks.
Another one I've found is this style, which various youtube videos (including Donnyboy) use to test for carb leaks.
Not too sure what the gauges are used for though. There's cheaper versions on ebay/aliexpress too.
Originally Posted by Mowerfreak
I would just run cleaner through it and perhaps a kit.
Just wondering, do you ever put a little Acetone in the fuel to help clean the carburetor? I heard a little bit can help clean it out, as long as you don't use Acetone often or a lot of it, it would be fine with the seals etc.. in the carb.
I agree with AVB and would just buy the alloy MityVac that has pressure and Vacuum ,a lot of the cheaper products don't last and some you can spend $40. and they don't work from day one,
If I bought something else I would buy the $36. pressure tester and buy a separate Vacuum tester.
it's probably worth you getting something affordable for the home tinkerer since you concentrate on the diagnosis side? What do you do after you discover a leak or a blockage? Is it just an elimination strategy or just a way to check for yourself to aid a repairer or ensure they don't take you for a ride?
I haven't tried adding acetone to the fuel and not sure of it's effectiveness. How much would you put in?
There's a regular Perth based poster who hasn't posted in a while who would be useful to this discussion. His username is Tylmond or Tyler, something like that.
Last edited by Mowerfreak; 21/06/2301:07 PM.
Ahh, if only victa had kept producing the thumblatch catcher series, they would be in better shape today!
If you want something cheap you can use a compressor with a regulator to adjust the high pressure to low pressure.
Blood pressure bulb may work as a pump for low pressure, you can use a syringe for a vacuum pump ,there are a few how to youtube clips on making them.
I usually just use BP ultimate fuel to clean a carby out but the main jet must be cleared out first otherwise the motor won't run ,just have to use fuse wire up the main jet to clear it.
I agree with AVB and would just buy the alloy MityVac that has pressure and Vacuum ,a lot of the cheaper products don't last and some you can spend $40. and they don't work from day one,
If I bought something else I would buy the $36. pressure tester and buy a separate Vacuum tester.
Hi Max. i'm leaning towards the little thumb pressure tester at this stage and maybe later get a vacuum tester down the track.
Originally Posted by Mowerfreak
it's probably worth you getting something affordable for the home tinkerer since you concentrate on the diagnosis side? What do you do after you discover a leak or a blockage? Is it just an elimination strategy or just a way to check for yourself to aid a repairer or ensure they don't take you for a ride?
I haven't tried adding acetone to the fuel and not sure of it's effectiveness. How much would you put in?
Hi Mower, I'm leaning towards a little thumb-operated pressure tester I think. The MityVac is a nice unit, I see 'Vintage Engine Repairs' on youtube using it also, though as I don't generate income from fixing/selling small engines, it's a bit much for my wallet at this stage (maybe later down the track).
I'd want to use it for process-of-elimination. I always clean the carbs with carb cleaner or fuel (in Ultrasonic cleaner too) and replace gaskets, though I admit sometimes I might reuse a gasket if it looks in good shape and not damaged, but being an old gasket, it could be stuffed even if it looks ok. Everytime I 'repair' something, I'd have to order kits as I don't keep a stockpile on hand. Testing the carb after re-assembly would help if the machine still wont start/run right.
As for Acetone, it's just something I briefly read, that if you get a small engine that's running poorly, mix a little (unknown amount) Acetone in with the fuel, the Acetone suppose to help cleanout the carb as the engine is running, making it (not always) run smoother 'if' it's a dirty/clogged carb. If it works, certainly beats tearing it down to clean (then replace gaskets etc..). Never done it myself though, just something I came across.
Originally Posted by maxwestern
If you want something cheap you can use a compressor with a regulator to adjust the high pressure to low pressure.
Blood pressure bulb may work as a pump for low pressure, you can use a syringe for a vacuum pump ,there are a few how to youtube clips on making them.
I usually just use BP ultimate fuel to clean a carby out but the main jet must be cleared out first otherwise the motor won't run ,just have to use fuse wire up the main jet to clear it.
I haven't looked at this how to video.
Thanks for the suggestion, not a bad idea . I have a compressor, will have to check out the regulators for it.
I'll check out those clips too, seems like a good DIY tester.
Sometimes I get 95 fuel and use it in the mower, not often though, may have to get a couple litres. Can you use 95/98 with stroke or do the cleaning additives affect the stroke fuel/oil mixture?
I usually strip carburetors right down (removing jets and all) then put it in the ultrasonic cleaner, followed by a blow out.
I came across another vacuum / pressure tester too, similar to the MityVac.
Hi Widget, As for the acetone don't waste your time with that idea. I was at a mates place last night and the carby on his ATV ( it hadn't been used for many years) and it started dumping fuel on the floor. Pulled the carby off and pulled the float bowl off and it had a green film all over the inside of the bowl. Mate grabbed his bottle of acetone saying this will clean it up. After leaving the acetone in the bowl for 15 mins it did absolutely nothing
As for Acetone, it's just something I briefly read, that if you get a small engine that's running poorly, mix a little (unknown amount) Acetone in with the fuel, the Acetone suppose to help cleanout the carb as the engine is running, making it (not always) run smoother 'if' it's a dirty/clogged carb. If it works, certainly beats tearing it down to clean (then replace gaskets etc..). Never done it myself though, just something I came across.
Sometimes I get 95 fuel and use it in the mower, not often though, may have to get a couple litres. Can you use 95/98 with stroke or do the cleaning additives affect the stroke fuel/oil mixture?
Never had problems using 98 since 2017. best I have used is ampol 98 - no idea what they put in it but several of my machines started running noticeably richer after running a few hours on it. was able to lean out the carburettors so it obviously cleaned something out.
Don't bother with acetone. Acetone is the main ingredient for carby spray, but it needs to be mixed in with xylene and tolulene to have good effect. also, stick a nitrile rubber glove in acetone and stick another in petrol. The acetone will attack the glove. Carby diaphragms are (predominately) nitrile.
Go down to bunnings and grab a 120ml bottle of "mechanic in a bottle". Sounds like a scam but it has saved me going into countless cheapo trimmer carbies I really didn't want to stuff with.
I think you are just throwing away $40 if you buy a cheap tester may as well make a tester from a bike pump etc and make a cheap Vacuum tester or spend more if you want a MityVac.
Yes I've also had a few engines that hunted down low and used 98 fuel and after a while they run smooth again.
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