# 2 cycle carb questions



## TownWrench (Sep 27, 2005)

_what are the professionals doing? When i clean a carb i use brake clean or carb cleaner and low air pressure.i have never removed the welch plugs nor do i do i have a ultrasonic cleaner.75% of the time it seems to work.but not lately.seems i've been wasting labor time and parts only to find the carb is bad.when does it pay to just buy a new carb.after cleaning and installing the kit now i have to remove the carb again. Also is anyone pressure testing them these days?i had an old tillitson carb that will only run with the choke almost closed.and this was after cleaning and a new kit, still runs on choke mostly closed and still is very hard to start.also what are the symptoms of bad check valves? Please answer all questions. Thanks 


townwrench_


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## billsmowers (Mar 21, 2008)

All my carbs go in the ultrasonic cleaner first then a new kit i do not remove the welch plugs unless i have to i have a hour labour up front if it is a carb i do not think i can fix and the customer will not have a new one fitted

bill


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## RKDOC (Jun 20, 2006)

I pressure test all carbs on the machine. If the pressure tests bad then I check on the price of a new one. If the price is $60.000 or less I just replace the carb. I am by no means a pro, this is just what I do.


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## geogrubb (Jul 28, 2006)

I do a visual check of the equipment to get a general mental opinion of how it has been treated, then do a smell check of the fuel tank and air filter area for the old paint can smell, after cleaning the exterior of the carb, I will dis-assemble and check for obvious crud the hold the carb in a clean paper towel and spray all holes cracks and crevases with brake parts cleaner, then depending on the amount of residue in the paper towel, I will put a kit in or a diaphram/gasket or scrap it. I have the compressor, it destroys check valves, I have ultra-sonic cleaner, it destroys the castings, I have soak(NAPA 6402), but why, if it is a cube carb and can't be cleaned with brake parts cleaner it is a waste of time and resources, IMHO. Have a good one. Geo


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## billsmowers (Mar 21, 2008)

geogrubb said:


> I do a visual check of the equipment to get a general mental opinion of how it has been treated, then do a smell check of the fuel tank and air filter area for the old paint can smell, after cleaning the exterior of the carb, I will dis-assemble and check for obvious crud the hold the carb in a clean paper towel and spray all holes cracks and crevases with brake parts cleaner, then depending on the amount of residue in the paper towel, I will put a kit in or a diaphram/gasket or scrap it. I have the compressor, it destroys check valves, I have ultra-sonic cleaner, it destroys the castings, I have soak(NAPA 6402), but why, if it is a cube carb and can't be cleaned with brake parts cleaner it is a waste of time and resources, IMHO. Have a good one. Geo


Geo what cleaner are you using in the ultrasonic cleaner? the chemical i use will not harm the castings it is made for carb cleaning

bill


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## geogrubb (Jul 28, 2006)

billsmowers said:


> Geo what cleaner are you using in the ultrasonic cleaner? the chemical i use will not harm the castings it is made for carb cleaning
> 
> bill


Plain water, water and Dawn, water and Zep Purple, all purpose ultra-sonic cleaner from Harbor Freight, I didn't read the small print on the ultra-sonic cleaner until after one carb turned black, I shouldn't have used it at all on the cast carb. Have a good one. Geo


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## duffer72 (Jul 23, 2011)

If customer will not put $ up front for labor and kit I won't touch them other than replace the carb, been burned too many time particularly on the cheapo units, if clean and kit don't work for those prepaid I will install a new carb at no additional labor charge. If it's not worth the risk to the customer it certaintly is not worth the risk to me.


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## 30yearTech (Sep 14, 2006)

TownWrench said:


> _when does it pay to just buy a new carb.after cleaning and installing the kit now i have to remove the carb again._


The rule of thumb that I use is; if it's an adjustable carburetor (High & Low speed adjustments) I will go ahead and kit it as they usually will work alright. If it's a new non adjustable, I will tear down for a visual inspection. I may try cleaning if there was visible debris inside the carburetor, but I won't kit it. If it's reasonably clean and was not working good, it gets a new one if the customer is willing to spend the $$.


TownWrench said:


> _is anyone pressure testing them these days?_


I only pressure test if I am having problems with the metering needle not seating good or carburetor is flooding.


TownWrench said:


> _i had an old tillitson carb that will only run with the choke almost closed.and this was after cleaning and a new kit, still runs on choke mostly closed and still is very hard to start.also what are the symptoms of bad check valves? Please answer all questions. Thanks townwrench_


Bad check valves on newer carburetor with an attached purge bulb will not circulate fuel with purge. The carburetor will lean out and die when you throttle it with a bad high speed check valve, but will generally idle alright. 

It sounds like the Tillotson may have a bad high speed check valve, or the main jet is still restricted.


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## WINDOWMAN (Sep 25, 2007)

*windowman*

I am from Cedar Rapids Iowa
I am mostly retired after 40+ years in the auto repair business owning my own Independent shop for the last 20. After not being geared to sit around I started working part time at a local True-Value Hardware store repairing windows and screens. The store has a Rental Department and I made the mistake of showing some mechanical ability. From minor repairing Rental tillers and such it has grown to lawn mowers, snow blowers, blowers, chainsaws and whatever else looks interesting.
The 4 cycle stuff seems pretty basic. The 2 cycle trimmers,blowers,saws and such are a real challenge for me as I am old enough (70) to tire easily on the multiple pulls of the flooded ones. I have a hard time pulling them fast enough for a good spark with the spark plug in. Remove the plug no problem.
Maybe I should leave those for the young guys.


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## RKDOC (Jun 20, 2006)

I went to an Echo training school where the instructor told us to do the following on two stroke engines. 

Pull fuel filter from tank and remove fuel filter. Connect vacuum gauge to the fuel line. Pump gauge to 10 pounds pressure. It should hold for a couple of minutes. Then depress primer bulb, with each pump of the primer bulb the pressure should go down, then hold until the net press of the bulb. This tests the function of the needle and seat. When all the pressure has been expelled, continue pumping the primer bulb. The gauge should show vacuum. If gauge does not show vacuum, then the high speed check valve is bad.

Hope this helps


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## keb (May 26, 2010)

RKDOC thanks ....I was ready to give up 2cycle.....You made my morning!


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## Rentahusband (Aug 25, 2008)

geogrubb said:


> I do a visual check of the equipment to get a general mental opinion of how it has been treated, then do a smell check of the fuel tank and air filter area for the old paint can smell, after cleaning the exterior of the carb, I will dis-assemble and check for obvious crud the hold the carb in a clean paper towel and spray all holes cracks and crevases with brake parts cleaner, then depending on the amount of residue in the paper towel, I will put a kit in or a diaphram/gasket or scrap it. I have the compressor, it destroys check valves, I have ultra-sonic cleaner, it destroys the castings, I have soak(NAPA 6402), but why, if it is a cube carb and can't be cleaned with brake parts cleaner it is a waste of time and resources, IMHO. Have a good one. Geo[/QUOTE
> 
> This it pretty much what I do also.


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