Replace an expensive obsolete carburetor with a cheap similar one?

Hello,

I have a question regarding carburetor replacement that I hope someone might have advice on.

I was wondering what might happen when a carburetor is installed on an engine that it isn't designed for but actually fits correctly? I have an old lawnboy push mower that has an unrepairable carb. It will cost $70.00 to replace, and I have found several carbs that seem to have the same identical housing and connections for around $9.00 - $14.00. I do see internal differences, but they look like they would fit perfectly from a mechanical sense.

I know that this can be done in different instances because I've replaced many other obsolete parts on machines with cheaper and often better new parts. I would guess that my carb is obsolete which makes it so expensive to replace. I don't really think that it's packed with anything special that makes it more expensive than the cheap ones.


If anyone has any thoughts on this I would appreciate your advice.

Here is a link to the original carb (a Tecumseh 640288 Carburetor) $70.00:
https://www.amazon.com/d/Carburetor-Rebuild-Kits/Tecumseh-640288-Carburetor/B0074BT8TC

A link to the cheap and very similar carb (fits Tecumseh 632795 632795A 633014 and more) $12.00
https://www.amazon.com/shiosheng-Ca...t=&hvlocphy=9006458&hvtargid=pla-763947885035

Also a link to a carb that seems to have similar internals but with an extra port on the outside.
https://www.amazon.com/dp/B07FYM35Q...&pd_rd_r=8afc74fc-91cb-11e9-97ca-c105db7db679

Thanks in advance for any advice. I really appreciate it.
Regards,
Tim

This it?
https://www.ebay.com/itm/Carburetor...Tecumseh-Engine-/171407755626?redirect=mobile

A carb is a carb is a carb is a carb.
So any carb CAN be made to work with any engine.
Governed engines are little more tricky as you have to match the movement of the governor to that of the throttle butterfly.

As for cheap carbs bought on line.
Stop & think about the price.
Take out the Amazon fees, then a 10% to 50% profit, then shipping and have a think of the ex-factory price.
A lot of what is offerred on like are trash items that failed quality control , were rejected by the original customer and sold off by the factory as scrap.

Also a lot off them "fit" a particular engine and "replace" a particular listed carb, but they are not the same .
Float bowls are generally smaller as are things like needle jets .
So when you buy them you need to also buy spares because the next batch might not be the same as the previous.

If it fits, it works.

A carburetor is a rather simple device.
You can easily make one. Put a drinking straw in a glass of water and blow across the top of the straw. As you blow across it, the liquid will rise in the straw.
That's how a carburetor works.

If it supplies the engine with fuel as air passes through, it works!

Obviously, it has to fit properly, and supply the right amount of fuel to the engine. Just hope the jets are mated properly.
Most 'fake Chinese' parts are just replicas of the original one. Most of the time, I can't tell any different, but just assume there is some in materials quality and other detail areas.

For $15, buy it and find out.

Scrubcadet10 said:

This it?
https://www.ebay.com/itm/Carburetor...Tecumseh-Engine-/171407755626?redirect=mobile

Click to expand...

Scrubcadet,

That one seems almost identical with the exception of the extra butterfly valve. Mine only has one.
The link below shows one almost identical to mine.
https://www.amazon.com/d/Carburetor...288-Carburetor/B0074BT8TC?tag=viglink22747-20
Thank you.
Regards,
Tim

bertsmobile1 said:

A carb is a carb is a carb is a carb.
So any carb CAN be made to work with any engine.
Governed engines are little more tricky as you have to match the movement of the governor to that of the throttle butterfly.

As for cheap carbs bought on line.
Stop & think about the price.
Take out the Amazon fees, then a 10% to 50% profit, then shipping and have a think of the ex-factory price.
A lot ofwhat is offerred on like are trash items that failed quality control , were rejected by the original customer and sold off by the factory as scrap.

Also a lot off them "fit" a particular engine and "replace" a particular listed carb, but they are not the same .
Float bowls are generally smaller as are things like needle jets .
So when you buy them you need to also buy spares because the next batch might not be the same as the previous.

Click to expand...

Thank you BertsMobile
I totally understand what you are saying. The problem is that I pick up mowers off season for much less than the price of a cheap rebuild kit and it's hard for me to justify spending over $70.00 for a new carb.

I apologize for my post yesterday. I posted links to cheap Chinese carbs that really didn't look like mine. The carb that I was considering actually had the same exact housing with all of the same outside parts. My original was Chinese too so it might have come from the same casting.


I never used to buy anything Chinese and tried to get everyone else to do the same. Now everything is Chinese and I wonder which is the quality part and which is the factory reject.

Thanks for your reply.
Regards,
Tim

TerraForte said:

If it fits, it works.

A carburetor is a rather simple device.
You can easily make one. Put a drinking straw in a glass of water and blow across the top of the straw. As you blow across it, the liquid will rise in the straw.
That's how a carburetor works.

If it supplies the engine with fuel as air passes through, it works!

Obviously, it has to fit properly, and supply the right amount of fuel to the engine. Just hope the jets are mated properly.
Most 'fake Chinese' parts are just replicas of the original one. Most of the time, I can't tell any different, but just assume there is some in materials quality and other detail areas.

For $15, buy it and find out.

Click to expand...

Thank you for this TerraForte.

I think that I am going to buy one. I actually got the mower going yesterday - I guess i was too quick to say that the carb was not repairable. I realized that my pressure washer had the same identical carb and I cannibalized parts from it to fix the mower. Part of the problem (or maybe, all of the problem) was a collection of microscopic pin holes in the bottom of the float cup. The rubber cup washer was also pretty bad. I rebuilt the pressure washer carb a year or two ago but could never get the bowl float to completely turn off the gas. I'll try the new one on it.


Thanks for your reply.
Regards,
Tim

A factory that makes a good quality part puts it's name or the customers name on it.
The factory that does not want to be identified as the source of garbage makes sure there is no name on it.
That is a good place to start
Unbranded = highly suspect
Lots of after market suppliers , Oregon, Prime Line, Stens & Rotary
Their parts carry a real warranty

On Ebay you check the "Other Items".
If the seller is listing 16,000 items from condoms to lawnmowers then they are a disposal agent and very good chance the parts are defective.
If they only list engine parts then better than average chance they are selling good stuff.
Amazon will not allow you to do this so you have no idea when buying through them.

it is dead easy to build a web page to make it look like you are a real business when in fact you are nothing more than a computer is some ones garage buying junk from China then shipping it to Amazon warehouse for distribution to cheap sake mugs.
Check to see if the "seller" has a street address then google the address and see what is there.
You see a warehouse with their name on the outside good chance they are ligit.
You see an office block, no trucks then they are suspect.
I recall a clothing company offering very cheap printed T's & sloppy.
Googled them & found the address was a vacant block.

Tim:

For giggles and grins, I have to ask how you determined the carb needed replaced in the first place (as opposed to just needing cleaned etc). Not trying to slow down your progress but I've worked on many an engine that had this carb and 99 out of 100 times the main jet was clogged. I've run into worn throttle shafts or a dried out primer bulb, but it's rare. I have only replaced one with one of the Chinese knockoffs due to physical damage to the original carb and the knockoff worked great. I even like that the main jet was adjustable like they were in the 'old' days. Parts for the original carb are still available. Just wondered....

I'm showing my age because all too often now entire assemblies are pitched when a little TLC on the original is all that was needed!

Good luck!

Telesis said:

Tim:

For giggles and grins, I have to ask how you determined the carb needed replaced in the first place (as opposed to just needing cleaned etc). Not trying to slow down your progress but I've worked on many an engine that had this carb and 99 out of 100 times the main jet was clogged. I've run into worn throttle shafts or a dried out primer bulb, but it's rare. I have only replaced one with one of the Chinese knockoffs due to physical damage to the original carb and the knockoff worked great. I even like that the main jet was adjustable like they were in the 'old' days. Parts for the original carb are still available. Just wondered....

I'm showing my age because all too often now entire assemblies are pitched when a little TLC on the original is all that was needed!

Good luck!

Click to expand...

Telesis,
I got the mower going thanks to everyone's suggestions. I got really busy (I actually was overwhelmed with work while I was posting this post) and never did the right thing by replying and thanking everyone for their help. I did read your reply and your question stuck in my mind all summer and winter long. The short answer to your question is that I was stupid and that their must have been dirt somewhere, because I cleaned the carb again and the mower is now the best mower that I've ever owned. You were completely right in every aspect of your questions and now I think the same way. Thank you. Regards, Tim

Thanks to everyone for your help. I appreciate every suggestion.