OutdoorKing Repair Forum Forums Restoring, Customising and Modifying Tech Talk HONDA GXV140 self propelled.

I have found it, I was getting the mark on the flywheel mixed up with the starter cup mark, this is what I was trying to remember from when I pulled it apart.

I can't see how you can mess up the ignition timing on that engine Mark - if you've found a way I'd be interested. It seems to me that if you put the flywheel on the key, and bolt on the ignition unit in the only place it will fit, the timing is correct.

There is a reason to have the TDC mark. Because Honda does not use a timing mark on the crankshaft timing gear, to reassemble the engine without making a timing mark, you have to put the engine on TDC, then slide the camshaft timing gear into position so that its timing mark is at the closest possible point to the hub of the crankshaft timing gear. Because the timing gears are helical, of course you have to lead it a bit so that by the time it rotates as it slides down into place, it is as close as possible to the crankshaft. Kind of reminds me of duck shooting.

Thanks, I am confident the timing is correct.
Had a glass half empty moment.
I have done a bit more.
I have lapped the valves and am happy with the results.
Set the valve clearances.
Put the carby together, I wish it was better, it didn't clean up real well.
Here are some images of where it at.

Hello, I have had the engine running.
Started very easily, no internal noises.
When I take it off choke the engine dies.
So, I figure it is a fuel restriction.
I will put so images up of the stripped carby, so you can see what condition it is in.

Bugger that's no good like you say sounds like a fuel issue so carby...Am sure ive got a good carb off a GXV120 in the parts bin,I will have a look if I do will pm you and send it out to you...It looks the same as the one you have only thing different Id say would be jets so swap them out to the correct jets and should be good to go thats if they are the same carb?......

Hello,
Chris that is a kind offer, let me have another go at cleaning it first though.

I don't normally do anything different from soaking it in fuel and spraying galleries with carb cleaner.

I have done some more cleaning, jet and emulsifier are fine. I suspect the galleries. I have it soaking in fuel. I will watch the cleaning video again and read up on cleaning again. I will let you know how it goes.

I had the engine running for quite a while yesterday on choke, it is running great.
But breaking down and stalling as soon at the choke plate starts to opened.
I will put it all back together and let you know the results.
cheers

First, the GXV120 and GXV140 carburetors are slightly different. The biggest difference is that the GXV120, like the GXV160, has a fuel tap built into the carburetor. On the GXV140 the fuel tap is separate, further up the fuel line. A second difference is that the drillings in the emulsifier are slightly different. The main jet is the same.

Mark, the way you clean carburetors will not work on Hondas, though it may on Briggs engines. Honda's Keihin carburetors form hard gum deposits, particularly in the main jet and emulsifier, that will not be affected by soaking in petrol. Even soaking in carb cleaner will only soften the gum, not remove it. I've also tried using an oxy torch tip cleaner - it has very little effect. You need to blast carb cleaner through every one of the holes, then follow with a tip cleaner or the correct size of jet drill bit (the drill bit is better of course). Here is a video showing how to do the job properly:



Having said all that, the problem you have described is not due to gum in the jets, unless the main jet is almost plugged. It sounds as if you have a fuel tank, fuel line or needle-and-jet obstruction that will only pass enough fuel for the engine to idle. I suggest you just remove the drain plug from the float bowl, put a cup under it, and observe the flow rate of fuel out of the drain port, with the fuel tap turned on. If my guess is correct, after draining the float bowl it will just drip out.

Hello Grumpy, I did your trick to test fuel flow, I am happy that it is OK.

I soaked the carb for a day in fuel ,then sprayed all the openings and galleries with carb cleaner.
I payed more attention to emulsifier, I see what you mean now about gum. I put an oxy tip cleaner through the middle and each time I had to wipe it clean with a rag. (I thought it was clean)

Put it all back together: engine starts first pull, when I take it off choke it stays running now, it will run on fast, slow and idle.
But it is running like a hairy goat, missing on all speeds.

So, I have to get a bit more serious with cleaning this carb.
I will buy some of those jet drills.

It takes brain power and time to respond to my threads, thanks

Mark, you are contributing at least as much as you are getting around here, and your cases go on record to help other people, so you are adding value to the site. No thanks are necessary.

For people who are used to pre-emissions Briggs engines, becoming accustomed to modern carburetors takes an effort. Fortunately the Keihin carburetors used on OHV Hondas, and even the Ruixing copies used on chondas, are decently designed and made, so once you make the mental adjustment it is all straightforward. Remember though, that main jet was drilled to 0.55 mm at the factory. My own GXV140 was a bit gummy when I bought it, and it took some work using the old elbow-grease methods to get a 0.45 mm torch tip cleaner through it. At that point it ran reasonably well - just about faultless except it required choke for about 20 seconds after cold start. (There was also an extremely slight stretchiness when the speed was increased, but you'd have to be an experienced car-evaluator to detect it.) So, I gave that main jet a single blast through its throat with carb cleaner, and it opened to 0.55 mm. Ever since then, the choke can be opened completely the moment the engine starts, even in mid-winter.

I think you'll find that some of your emulsifier holes are still blocked, and the remainder are well under-sized. One of the tricky things about carb cleaner is that it doesn't do much when sprayed on blocked holes - it has to flow through them to have its proper effect. Have you watched the video in my previous post yet? The guy isn't kidding - you need to follow that procedure to get a perfect result first try, with Keihin carburetors. It is quicker and easier just to clean the carburetor properly, than to mess about doing the job three times and curse everything and everybody in between tries.

When I started with the Hondas I resented the cost of carb cleaner. My first can cost $8 from a speed shop - but it took me a year and a half to empty it. Then I bought 12 cans for $53, and I'm pretty relaxed. 12 times a year and a half is 18 years. I'll be quite chuffed if I'm still above ground at that point. Managing the underside of daisy roots requires little or no carb cleaner.

I'll move this thread to Tech Talk.

Yes, I watched the video Grumpy and did some more cleaning.
I think the emulsifier is the issue, when I spray carb cleaner into it whist blocking one end, I expect to see a uniform spray coming from the small holes, I'm not getting that.
I attempted using my orbital sander. I had a piece a fibro in between the sander and the carburetor, as the sander is an ignition source.

I have put it back together and tried it again.
Starts first pull and is running better, still not running as smooth as Id like. It gets better as it warms up.
So, each time I have done some cleaning there is an improvement.
I am pleased the engine work I did is OK, just have to sort the carb when the jet drills arrive.

All 3 cables were seized up, speed select, stop run cable and SP cable. I snapped the stop run cable, the inner core was rusted solid to the outer, You might notice where I silver soldered it in one of my images just so I could test the motor.
I cant free up the SP speed select cable, the SP cable moving but I will replace it.

I operated the self propelled and it didn't work. I thought the worst - faulty gearbox or cable not set right, then I noticed the rear axle spinning but not the wheels. I ended up having the drive ratchets on the wrong wheels.
The one on the left side in the image goes on the right wheel. obvious now looking at the pawls.

I am confident that this will be a good mower to use once the carb and cables are sorted.

You are going through all the right processes Mark - it certainly looks to me as if you are earning success, and you will achieve it. Better still, by now you are pretty familiar with the architecture of that machine, and therefore with Honda OHV self-propelled walk-behind mowers. Every one you work on from now on will be relatively easy.

One of the things you are learning is that hard gum is pretty difficult to get off, and on a modern emissions carburetor it has to be removed to get a good result. FWIW, in my experience so far the GXV140 accumulates more of the stuff than other Honda engines. By the time you know what it takes to get a GXV140 clean, you should be able to handle the others quite easily.

As you said, you should get a uniform line of carb cleaner coming out simultaneously from every one of those holes in the emulsifier. Until you do, you can't expect it to run with the incredible smoothness of a well-tuned GXV140. It's almost eerie - extraordinarily smooth, so quiet that if you mow with the engine idling (which you can in short grass, provided you have 4 sharp blades fitted and you only require a Victa finish, not a Honda finish) you'll find the loudest sound you can hear is the grass hurtling around the scroll to the catcher. At any speed from just above idle, you'll find it takes quite a bit of grass to make any difference at all in the exhaust sound: that engine has rather a lot of torque.

When you get those jet drill bits, aside from being careful not to break them (the tiniest one is the one you use most, and it is only 0.012" diameter) you need to be careful not to leave a trail of inadvertently drilled-out jets and emulsifiers behind you. Until you know the size of the hole, try to avoid rotating the drill bit when you push it through, and where possible, push it through blunt-end first. A brand new HSS drill bit goes through a slightly undersized hole in brass very easily, cutting the brass like butter. With emulsifiers there are normally only one or two sizes of lateral hole. If you get one of them at the top clean, and one of them at the bottom, you can then select the drill bit which fits each of them dead-size, and put it through all of the others of that size, twirling it with the pin vice if necessary. You can then make a note of the sizes, and next time you have that type of Honda carburetor in front of you, you can go straight to the right sized drill bit in the pin vice, and twirl it through all of the holes in no time.

Hello, my jet drills arrived.
I am glad I wasn't impatient and waited for them, they were the right tool for the job.
The 0.45mm was the right size for the small holes in the emulsifier.
The 1.6mm drill went up the centre nicely.
I found magnetising a screwdriver made them easier to handle.


Because I took the carb off so many times for cleaning, I compressed the gaskets, so I coated the gaskets with non setting Master gasket - Loctite, I think this made a difference in how it runs now.

The engine has some unevenness whilst warming up, then come good.

It is not the prettiest Honda out there, but it is starting first pull and all working. First speed on the gear box is a nice leisurely walking pace, second speed pulls you along a bit.
I just have to keep an eye out for a catcher and a hub cap, then it will be complete. I would like three new cables, but these are working OK for now.

Thanks Grumpy for your help on this, I learnt a lot and I am very satisfied with the results and the way the mower works, it is a good machine.

Thanks for the report, Mark. I agree, the jet drills make it practical to do that job fairly easily. I haven't found any other way that will work as well.

The slight unevenness when cold sounds like lean mixture - mine doesn't do anything like that, but it did before I fixed two problems. One was cleaning the main jet thoroughly so it was 0.55 mm diameter. The other was fitting new genuine Honda intake pipe gaskets on both sides of the insulator. True, they are about $2.50 each, which I resent, but if you put them on dry, onto clean flat surfaces, they seem to last indefinitely - I've had them on and off several times without damage. It sounds to me as if you have one or other of those two faults.