Vacuum / Pressure

I've decided I need to build my very own Vac/P test kit.

I think the mightyvac is probably the better option, but I've seen some squeeze bulb setups.

That made me look at inline fuel primer bulbs for snowmobiles or small outboards, and they seem to be available, and Cheap.

I looked at a lot of old threads, but didn't see that anyone had used one.

Does anyone have any input on the amount of In. Or # these little bulbs will output?

Thanks.

Built my own pressure tester from a blood pressure cuff, tee connector, and a low pressure gauge from Grainger. you can turn the regulator on a compressor for the air supply also. As far as vacuum testing I just bought a Harbor freight special and it worked okay until I stepped on the gauge.

Jeremy

decableguy2000 said:

Built my own pressure tester from a blood pressure cuff, tee connector, and a low pressure gauge from Grainger. you can turn the regulator on a compressor for the air supply also. As far as vacuum testing I just bought a Harbor freight special and it worked okay until I stepped on the gauge.

Jeremy

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Thanks!

I've just been looking for low-buck options, and enjoyed The "Poorman's guide to Vacuum Testing" thread.

I built a pressure tester using an inline primer bulb. 15 psi. is the maximum pressure I can get from it. I discovered the check valve in the bulb was not that good and added an additional check valve after the bulb. Unless you already have the parts, I would go with the Mighty Vac. I built mine up from new parts, and had half the cost of a Mighty Vac when it was completed.

Oli said:

I built a pressure tester using an inline primer bulb. 15 psi. is the maximum pressure I can get from it. I discovered the check valve in the bulb was not that good and added an additional check valve after the bulb. Unless you already have the parts, I would go with the Mighty Vac. I built mine up from new parts, and had half the cost of a Mighty Vac when it was completed.

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Thanks! The 15 psi is the info I was looking for. That would be adequate for the job. I also agree that the mityvac may be the simplest.

I was re-reading the "Poorman's" thread and was reminded that someone had used a large vet syringe. That made me think of some old 'self loading' syringes that we once used for processing lots of calves. Hmmm

A cheap source for a good gauge is still lacking, and the mityvac comes with a gauge.

I pondered building one. Look up sphygmomanometer bulb on ebay. You can get one for $4.50 free ship.

I ended up getting the mityvac. Probably the better choice since it comes with so many tips that make it useful for other applications.

You can get a carb vac/pressure test gauge on ebay for pretty cheap. But I would recommend a mightyvac kit, it comes with everything you need and you know it works. Good value for money.

Oli said:

I built a pressure tester using an inline primer bulb. 15 psi. is the maximum pressure I can get from it. I discovered the check valve in the bulb was not that good and added an additional check valve after the bulb. Unless you already have the parts, I would go with the Mighty Vac. I built mine up from new parts, and had half the cost of a Mighty Vac when it was completed.

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Oli, would you say that you're happy enough with the way yours works, both in vacuum and pressure? Hard to squeeze or no?

Rudolf73 said:

You can get a carb vac/pressure test gauge on ebay for pretty cheap. But I would recommend a mightyvac kit, it comes with everything you need and you know it works. Good value for money.

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I'm starting to lean that direction. Thanks.

In response to dl5205, At 15 psi, the primer bulb is tough to squeeze. I use it primarily for 2 cycle carb testing and usually pump it up to around 7 psi which is easy to do. I do not use it for vacuum testing. Not sure how well it would work for that. It works fine for what I use it for, but I built it up with new parts, and probably spent $30+. I think the MightyVac would be a better value if you want to do both.

I originally went with the mityvac MV8000 and used a small compressor for pressure. I eventually went with the MV8500 because it does pressure and vac. Much easier to just flip a switch and get pressure than screw around with the compressor.
I still need to hook up the compressor for difficult to find pressure leaks.

I posted this in the swap meet. I have a bunch of regulators I picked up. A few have small PSI output gauges 0-30psi and 0-60 psi. Some of the others can prob have the output gauge swapped to do the same. I hooked mine to my compressor to test carbs and saw seals. I still use a hand vac pump from the autoparts store for vac test though.

dl blood pressure cuff bulb will pump plenty of pressure plus it has the relief valve on it which the fuel bulb don't. I would recomend you build a cheap unit based around a large 4"to6" vaccuum/fuel automotive type gauge. This type gauge reads press and vac on a low scale thats perfect for saws and are very easy to read.Just use long vac hose from gauge to tee(this lets you hang gauge above bench out of the way but easily readable) then a short hose to tee and med hose to hook to bulb or vac pump oh hook short hose to impulse or spark plug hole via compression gauge quick adapter. Vac pump can be cheap HF type works great.Also the automotive vac/press gauge kit should come with adpters for different size hoses but I find most good vac hose has alot of stretch.
The reason for doing it cheap is the more you use it you will change things and modify how you test.I was going to build a double wam zoomie tester with regulator and console with gauges but one night I needed to test a saw so luckily after a scavenger hunt in house and shop I had my tester that was three years ago.The only thing I've changed is longer hoses.Once you do some saw you'll find you don't really need a compressor at lease I don't,if it's that bad it's usally obvious but you can add it easily.Really the block off plates are the pain,I have two exh. plates both have one hole and one slot and they cover alot of saws but you can use thicker rubber and your muffler.On carb side I find soft pine 2"x2" blocks work great as you can take a small rasp and contour them to fit all the knook and crannies plus the long studs.
Hope you did'nt fall asleep during all this,hope it helps and remember to press test every carb too. Ken

Thanks to all for the replies!

A comprehensive kit using the MityVac 8500 with sealing plates and a spark plug adapter and also a "bu;b" kit are available on eBay...search "2 Stroke Pressure & Vacuum Leak Down Engine"

No disrespect meant but most people should be able to suck the line down to about 6 or 7 using your mouth. I use the blood pressure bulb for the pressure test but I'm a tightwad and don't test the saws unless I think they need it.

Are you sure you don't want to rephrase that first sentence. I know what you meant but you really opened yourself up on that one. I kind of have a warped sense of humor

Ax-man said:

Are you sure you don't want to rephrase that first sentence. I know what you meant but you really opened yourself up on that one. I kind of have a warped sense of humor

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Nah, basically I was just quoting what someone already said on AS. I just remembered to re-state it. I did try it and could get around 6 on the gauge, have to have a shutoff valve to see if it holds though..
Most of the rebuilds can get by with just a pressure test, in my opinion.

I agree , but it never hurts to check vacuum just to be on the safe side. Most saws will flunk the pressure test but will pass the vacuum test.

Getting back to the thread . I recently had some mad money to spend and bought the 8500 MV kit. The tester is great but the kit leaves a little to be desired. It didn't have very many of the plugs and tips like the older model kit I bought years ago. Too much automotive stuff I'll never use. I wish now that I had just bought the next model down with just the tips and plugs without the so much automotive stuff. My older MV still works but I sucked some gas into by mistake and it never worked as good after that.

The only problem I have with pressure/vacuum testing is that every saw is different and you have to have a lot of different blockoff plates. Some of the saws like the older Stihls and Echos require taking almost the whole saw apart to get to it. The 041 I recently did is an example. I have an Echo 400EVL coming up that is about the same way, easy to block off the intake but not the exhaust..