OutdoorKing Repair Forum Forums Restoring, Customising and Modifying Tech Talk Chonda - Sanli Lazercut!

I have included a picture of back of the carby where I am talking about lining up the hole in the gasket. Just incase this might be the reason.

Having that vacuum tapping on the carburetor work properly matters, Jaffa, but it wasn't the issue that prevents it from starting when you put the top on the air cleaner box. It's a basic rule of scientific investigation: cause and effect. If you put the top on the air cleaner, it won't start. If you take the top off, it will. You have repeated that experiment at least twice, and got exactly the same result each time. Therefore you only need to look at things that are different when the top is put on the air cleaner box.

Ok thanks. I'll take another look tonight and let you know how it goes.

I was thinking the placement of those gaskets might be restricting air flow and the opening of the air cleaner box helped the situation by allowing more air into the engine, thus allowing it to start easily.Most likely I am wrong.

At the moment Im fresh out of ideas unless you have anymore?

I think it is just a matter of making the checks I've asked for Jaffa. Is the air cleaner's air intake clear? Some pictures would help us keep track of what you find.

I can assure you the intake is 100% clear. I did the same test as Rob, very simple but effective (that is shoving a towel down it). I will get a photo of my intake tonight after work as you requested.

It was running before the carby clean albiet rough with the cleaner cover on and I havent changed anything on the intake or cowling configuration.

I will get you some more specific photos.

Going back to your last photo Jaffa the hole in the gasketis not supposed to line up with the hole in the carby and in your previous photo to that of your gasket and spacer is wrong or it is different to mine.

This is how they should look all lined up ,all three with the hole on the left . This is what you should see just before you mount the carby. Ignore the square edge on the green one as ,pretend it's round.

This is the assembly instruction drawing for those parts.

Hi Jaffa, i've been following the thread and you've got the pros on your team on this one. I will add/re-confirm one thing though; The 2 gaskets and the spacer play a huge part in that machine running right. The first gasket, which goes on the engine side, and the insulator are pretty straight forward. The final gasket is the one that will definitely give you grief if not put on in the right position. The little hole must be on top and off to the left a little when installed, exactly as set out in Roebucks pictures. I noticed in your photos you have it on wrong. Once installed correctly the bottom of all 3 gaskets will line up flat along the bottom edge.
Bassic deductive reasoning tells us it was running ok prior to the carby clean. So either the gaskets are all jumbled up and incorrectly placed or the carby is stuffed, which i doubt as it runs sweet when the air filter cover is removed.

The GXV140 has a D-shaped intake port, which shows you which way to put on the gasket on the port side of the insulator. Then you put the insulator on with the air passage positioned away from the engine, toward the carburetor, and with the entry port for the air passage facing downward so it won't collect dirt, and the matching port in the carburetor in the same position when you install it:


Note the yellow oval on that picture. Put the hole in the second insulator gasket over the top of that yellow oval, so that it communicates with the clean end of the air passage in the insulator.

Then there is only one way you can put the carburetor on, unless you want to have the float bowl upside down:


Now unfortunately I feel obliged to explain what all that stuff does, which will condemn this thread to ending up in Tech Talk.

The carburetor appears to have been designed for that system to be the float bowl vent. Here is a top view of the carburetor:


The yellow oval shows the path of the horizontal passage in the carburetor, of which the port we have been looking at is the end point at the right hand end. The red circle shows a vertical passage down to the float bowl compartment, matching that horizontal passage.

Now let's look at the underside of the carburetor, above the float bowl:


The red circle shows the underside of that vertical passage that we've just examined from the other end. If you look at it very closely, you'll see that there is no lateral port at the bottom of it, heading off to the left, toward the port in the carburetor's mounting flange. I've verified this by probing the passages: the passage from the flange to the vertical passage is blanked off. After providing elaborate tooling in the insulator and the carburetor mounting flange, plus the horizontal and vertical passages in the carburetor, Honda decided not to use them, probably because of the possibility of dirt entering the float bowl through that system. Hence it seems it makes no difference whether you misassemble that system or not, since it isn't being used.

So how is the float bowl vented, I hear you cry? Check the green circle. This is the actual float bowl vent, which communicates with the air cleaner, and thus does not allow dirt to enter the float bowl. Note that all this does make it important to put the air cleaner mounting parts together the right way around.

I must confess I didn't know until I did this check this morning, that the air passages in the insulator and flange are dummies - so the exercise has been interesting, and perhaps useful.

Thanks for your efforts guys.
I now have the gasket, insulator and insulator gasket positioned exactly as per Roebucks photo and grumpy�s schematic.
I have also attached some additional photos of the air box assembly to check for any abnormalities when compared to Rob�s photos.
I personally cannot see an incorrect way to install the air box however I have attached some additional photo�s grumpy as you requested.
The first photo shows were I have removed the breather hose to check for blockages � nothing found. I also check the joining arm to the airbox which is quite small and it wasn�t blocked.
The second photo shows the airbox mounted with the breather hose removed.
The third photo is the top view of the airbox.
The fourth is the underside of the airbox cover.
The fifth photo shows me about to re-install the cover.
The air passage I can assure you is 100% clear.

Let me try to summarise. If you do not disturb anything else, but you put the lid on the air filter box, it won't start. This applies whether or not there is a filter element in the box. However if you remove the lid, it will start, whether or not there is a filter element present. Please confirm that this is correct.

If that is correct, I think the next thing to try, is putting the lid on the box but not screwing it down: push it down into place, but do not put the nut on the top. If it still doesn't start, lift the lid about 1 mm and let it sit there, still without the nut, and try again. (This is aimed at seeing whether the problem is distortion caused by the clamping nut on the top of the box.)

Thanks for your patience grumpy.
I didnt get much of a chance to test the mower but I did give it a short go after confirming I put the gaskets in the correct position.
- The mower didnt start with the air cleaner and airbox cover in place.
- I removed the airbox cover and the engine started.
- I then removed the air cleaner and replaced the cover (full screwed down) and it started.

The air cleaner was very clean however upon realy close examination it appears someone has oiled the cleaner and not just the prefilter. Could their be a reason for this or perhaps a fault in manufacturing?

Lastly, I bought a new filter last night so I will see if that solves the final problem after work tonight.

There is a technology that oils paper filters Jaffa, and it works when it is done that way, whatever that way is (the paper finishes up a pink colour). I suspect it involves using paper of an extremely, open porous nature, then oiling it very lightly with a very light oil. Obviously a soaking in engine oil, though, will stop any air getting through an ordinary paper filter.

If the engine will run without the filter in place, but won't run with it in place, the filter is blocked. The same thing can happen just through dirt accumulation, if an engine is used in a dirty environment without the air cleaner ever being replaced or serviced.

The big advantage of paper filters, in my view, is that if you use an oiled foam pre-filter in front of them, the paper part lasts pretty much forever and you can be confident that the engine is not inhaling dirt, so you can have your cake and eat it as well. Eventually the urethane foam pre-filter disintegrates due to the effects of oil on urethane, but then you can make a fresh pre-filter out of a very few cents' worth of foam.

Oh Jaffa, i warned you about those filters. It was probably all that was ever wrong with it.
A good learning curve though, well done, And for my 2 cents worth, and i know Grumpy will choose to differ, i wouldn't oil the prefilter, theyre generally pretty good because they pickup air from under the cowl which is generally less dusty than the outside air.

I agree with all of that except oiling the pre-filter bigted, as you predicted. I think they are almost ineffective unless oiled, so you have to replace the paper filter from time to time.

I'll leave this thread open, so Jaffa can confirm that he now has a sweet-running chonda - or if not, tell us about another fault or two.

I have also found these filters to allow no flow even though they appear OK. I put it down to poor crankcase breathers allowing a fine oil mist from the crankcase to slowly block the filter completely.

An interesting thought, rusty.ute. The breather hose enters the air cleaner outlet duct (carburetor inlet duct) quite a long way below the air cleaner body. Hence I don't see how oil mist could get up to the filter against the air flow unless there were substantial backward puffs from the intake port, through the carburetor, to carry the mist upward. There is always a small amount of puff-back due to the inlet valve not closing until after the compression stroke has begun. However if it were anything substantial the engine should need to have its oil topped up regularly, and probably there would be a smell of burned oil in the exhaust, and maybe a slight haze of blue smoke.

Having said all that, I don't like the plastic disk Sanli uses in the breather valve. We've already had a thread where it malfunctioned and caused oil to leak out of the breather hose where it connected to the air cleaner outlet duct:
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=52741#Post52741

I have found a couple of sanli in the past may of had the same trouble with the air filter , you could see the airfilter where holes had been made to let the air through which really made the filter useless but obviously kept the engine going or at least for a little while. If they bought another air filter it would of kept the motor running and given it proper protection .

Thanks for your help guys. This mower is now all fixed and running absolutely spot on. I took it out for a good test and it performed much better than expected. The new filter was the finishing touch.
All I can say to others is look very closely at the filter and whilst it may look clean the key is whether or not it has oil residue on it, I should have looked closer as bigted mentioned earlier. Mine did and until I took a closer look it caused me some frustration however the mower is now running spot on.

A good learning experience as you suggested Bigted. Hopefully it can be of use to some others.

Grumpy, Bigted and Roebuck thanks for your efforts. I appreciate the assistance. Time for this mower to keep working and staying off the scrap pile for at least a little while yet.

I must say these are a supprisingly sweet sounding engine.