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Crossy

One for the small engine experts (GX35 burning oil)

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Our 10 year old Patco-Honda brush-cutter has become increasingly difficult to start and now is definitely burning oil (exhaust smell), it also tends to peter out and stop. It's had a pretty good life really (Madam's family bought a cheap 2-stroke, it lasted less than a week).

 

So, I bought a new one, brilliant!

 

The engine on both is a Made in Thailand, Honda GX35. 

 

So now, is it worth re-building the old one? I can get a carb (with a "free" rebuild kit) for less than $20 and a piston with rings and gudgeon pin for less than $10.

 

I've not had the engine apart yet so I don't know what the bore is like, but assuming it's OK it's an engine re-build for $30 plus my time.

 

Question is, is it really worth it? Or should I just buy a whole engine?

 

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I had a similar problem with mine and took it down to Somchai Fixit in the village. 

 

He took it apart and found that it was beyond his skill level to repair. He showed it to me and told me that he could send it away and get it rebuilt. 

 

It took a couple of weeks and a couple of thousand baht and came back as good as new.

 

It is definitely worth it.

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Always a dilemma these days... I would say do it, just for your own satisfaction, if you have some free time... 

I just got home for a 2 week holiday and straight into a washing machine draining issue !! I bought a new one for 6000 baht, as this old one is about 6yrs old.. It just wasn't worth using up my time with this problem but I will sort it out at a later date. I know what the issue is after spending an hour on it... 

 

$30 is worth spending to have a reliable back up machine ?

P_20180818_115707.jpg

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we tend to buy new every 5 or so years, this year bought the honda gx35 also, just over 6,000 baht at dohome, i think they have got cheaper this year? before 8 or 9,000 baht? have many old hondas/makitas... still kept them running/fixing but at 6 ish new i will just buy new in the future.

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It's a math problem with a lot of unknowns:  

 

How long will it take?

How much are the parts (and tools) really going to cost to do it right?

What $0.50 part is going to delay the job when you can't find it locally?

How much is your time worth- including the time scrounging parts and tools?

What are the odds of screwing it up?

How much would a new Honda cost?
How long would a new one last?

Would a local brand like Polo (at half the price) be more cost effective than a Honda?

How much goodwill in the community can you get from giving the old one away to a neighbor with time on his hands?

 

If you enjoy working on engines, have plenty of time, and take pride in fixing your own stuff, go for it.

But even as a former grease monkey and semi-retired mechanical engineer, I'd go with a new Polo and cross my fingers.

 

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. I know what the issue is after spending an hour on it


Dodgy solenoid ?

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Usual when it is only oil usage you should look in the piston springs and valves. With a bit unluck also the cilinder.

 

But with saying this, these are themost expansive parts from the motor.

 

No need to start with exchanching the carburator.

Maybe start with the piston rings? Do you have possibilities to measure the cilinder? In fact you do not need to measure the exact size. Measuring difference between top diameter, middle diameter and bottom diameter will tell you a lot. You can try to place a ruler (knife edge ruler according Google translate) on the inside from the cilinder. When the gap you see in the middle is so big you can easy pass with your family and luggage, you should replace it. When the gap you can see changes a lot between inlet/outlet side, replace the cilinder.

 

I hope this helps a bit.....

 

Arjen.

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The carb definitely has issues, the check-valve on the primer lets air back and I suspect the diaphragm is on it's way out, for the cost of a new carb it's not worth faffing about re-building it. I'll probably end up doing it anyway mind, for a spare.

 

New piston with rings is on the list, I can re-grind the valves if they need it. As noted the cylinder is the most expensive bit, if it's badly worn or scored then time for a new engine, so task A is to pull the beast apart and have a look.

 

It's been a looong time since I re-built an engine, the last one was the Ford 2L cross-flow from my Transit (with a Capri cam and twin-choke Weber, went like a bomb, swallowed 4* like there was no tomorrow), probably back in 1990. The smallest I've done was a 250cc Matchless single (I wish I still had it, they fetch $$$ now), so 35cc is going to be fun, I have my head magnifier.

 

Once it's sorted I'll likely donate it to family ?

 

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3 hours ago, cornishcarlos said:

$30 is worth spending to have a reliable back up machine ?

And of course, I will be embarrassing myself by posting the gory details on Thaivisa.

 

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Go for it, I might do the same. But I am liking the backpack version of the gx35 as well. I might fix the old one and still get the new version.

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Posted (edited)

I have attached a list of parts in XL for the past 3 years.

 

A genuine Honda carb was 900 baht last year but you can get a copy for 600 baht.

 

Here is a link from the UK on all the parts for the Honda.

 

It gives the drawings and also the genuine part numbers.

 

http://www.diyspareparts.com/parts/honda/diagrams/umk435e-ueet/air-cleaner-7/

 

 

UMK 435 replacement parts cost.xlsx

Edited by billd766

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Remember that a cylinder never wears in a perfect circle but egg shaped due to gravity and piston thrust. The old rings wore in the same manor so they fit but now loosely. A new set of rings will be perfectly round and not fit the egg shaped bore.


Sent from my iPad using Thaivisa Connect

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41 minutes ago, Crossy said:

And of course, I will be embarrassing myself by posting the gory details on Thaivisa.

 

 I just finished a service on my strimmer with the GX 35 unit, still had the same issue with the engine cutting out after 15 min of use, I bit the bullet and let my Mr Fixit have a look, he told me it was the coil and after changed its been perfect.

 

 

Carburettor check sheet GX25-GX35.pdf

doc.pdf

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13 minutes ago, Isan Farang said:

still had the same issue with the engine cutting out after 15 min of use,

Ours sort of fades out once it gets really warm, I will certainly bear the coil in mind (it's actually a magneto, but the semantics matter not for our purposes).

 

One great thing about these ubiquitous little engines is that there are millions of them (and copies) out there so spares are readily available and low cost.

 

We have the advantage of being within easy striking distance of the farm shops at the back end of Rangsit market, never been let down by one or other of the "it's in here somewhere" shops ?

 

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3 hours ago, Crossy said:

The carb definitely has issues, the check-valve on the primer lets air back and I suspect the diaphragm is on it's way out, for the cost of a new carb it's not worth faffing about re-building it. I'll probably end up doing it anyway mind, for a spare.

 

New piston with rings is on the list, I can re-grind the valves if they need it. As noted the cylinder is the most expensive bit, if it's badly worn or scored then time for a new engine, so task A is to pull the beast apart and have a look.

 

It's been a looong time since I re-built an engine, the last one was the Ford 2L cross-flow from my Transit (with a Capri cam and twin-choke Weber, went like a bomb, swallowed 4* like there was no tomorrow), probably back in 1990. The smallest I've done was a 250cc Matchless single (I wish I still had it, they fetch $$$ now), so 35cc is going to be fun, I have my head magnifier.

 

Once it's sorted I'll likely donate it to family ?

 

If you into ford engines and a company with a machine shop second to none then check these guys out, I used them more than 40 years ago and they are still alive. http://www.burtonpower.com/

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