OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions on Other Engines Sanli chonda engine

Hi gents, long time between drinks, since my attempted rebuild of a Scott Bonnar, of which stalled due to a B+S engine that died badly.

Anyway, this is my latest issue. I have a Sanli power mulch mower powered by a chonda OHV engine. I have checked out previous threads dealing with a potential carby issue and have followed these as well-
-https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=43529
-https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=39098&Searchpage=1&Main=7398&Words=Ruixing&Search=true#Post39098
-https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=38603&Searchpage=2&Main=7309&Words=Honda&Search=true#Post38603
-Before I did pull apart the carby the mower was very hard to start on cold, and in fact all places. I checked the spark and fuel filter and they were ok. I removed the air filter also to no avail. I had to switch off the fuel stop and it started pretty much straight away. I think it was flooded, but I had to run it in cold start mode, as it would attempt to die on the run setting.

-I ended up followed the methods in the previous threads and ended up stripping the carby and cleaning it out. When I removed the float bowl, there was a rusty glug on the bottom which I think was also heated on around the bowl itself. It wasn't exactly the same in the above parts but close enough. I don't think I found any port blocked but I used the carby clean as the tool pick, so I am not sure. The glug I assumed was the general cause. I checked the gaskets and they all look ok. When I reassembled it, unfortunately it wasn't fixed. I may have to do it again, but this is why I thought to post my situation. I also not sure that my throttle cable is setting things right as there is a bit of play if you pull the cable, and the indicator isn't quite reaching the end stops. Also the link to a workshop manual isn't right anymore so I cant check the governor speed setting or the throttle adjustment either( I think its just the cable). I have had this for about 5/6 years from new, and nothing has been adjusted or changed.
- Since the clean the mower still is very poor at starting from cold, but I did get it to start after moving the throttle a bit. When it did start at cold, it splutters badly, but it really thrives well at the run position. It also doesn't slow down at all, until we go to stop, then quickly recover back a bit, which then is slower. Even at this point, beyond or higher than the run setting it splutters again. On reflection I am worries about an air port that I may have cleaned properly that feeds to the pilot jet. I have some pics of the unit and some during the first clean. I tried to do what has been said before in other threads first. Any advice is appreciated in advance.

Regards Eman.

I should add when I first got the mower, and for a few years after, it was indeed just a 1 light pull to start mower. The best I ever had.

Did you remove the main jet and spray tube and give them a good spray with carby cleaner and "stoke" the holes with a piece of bread tie wire,(a pick tool isn't small enough to get in there).
To assist in starting are you sure the throttle cable is fully closing the choke in the "start" position.
If it's not slowing down when you put it to "slow" it could be a couple of things:
1) are the linkages moving freely when everyting is assembled and the engine is off.
2) Ensure that the governor arm is tight and not slipping on the governor shaft.
3)try backing out the idle speed screw (it's the black plastic phillips head one in the front of the carby).

Try these simple suggestions, if you haven't already done so, and let us know how it goes

Hi Bigted,
thanks for the reply. Yes I fully disassembled the carby. I removed the emulsifier, but I didn't have a poke thru tool. So I sprayed the cleaner thru it and checked the holes to see if they were clear. Maybe that's not goo enough? Bread tie wire is a good idea and I might try that again if needed.
As to the fully closed section, I can try and place it right at the end of the stop and see if that works. I can also check the linkages as well, but I have to get my head around how they work. A manual would be a good idea to understand it all. I will also check the governor arm isn't slipping, as well as the idle screw.

Thanks for the ideas mate.

Ok I had another play with the mower. I lubed up the linkages with the throttle mechanism, and took of the air filter assembly. I used your idea with the bread tie, to clean the air intake to the pilot tube. While I did this I notice the main fly doesn't quite close the chamber fully, but am unsure if that is what it should be. I also notice that there isn't much change to the air intake via this and would like to know how the fuel system works to adjust RPM.

Anyway, after I did this, and everything was back on, low and behold the easy start was back. Just a simple pull to start and the engine ran pretty nice there and also in the run setting. It also had a noticeable slowing down of RPM as I went down the range to stop.

Unfortunately this didn't last. The starting is still perfect, but it runs very poor (it putt putts), with a dark exhaust. When it does it run pretty fast and well, but the change in speed isn't as good, and it basically stops on the spark cut off switch. So we are on the right track, but need a bit more work. If I had a write up concerning the throttle adjustment it would help, along with some info regarding the fuel/air actuation method. Here are some pics in the cold start and off throttle positions and the throttle mechanism positions.


Cold start, notice the slightly open fly position


Stop

You can get a bit more choke by gently bending down the tab circled in red seeings as your cable is already at the end of it's adjustment. This should solve your starting issue if you're not satisfied with how easy it starts. The more you restrict air flow on cold start up the easier it will start as manifold vacuum is forced to pull fuel up through the venturi to enable startup. With the choke not egaged all it does is suck air in from the filter housing.

As for your putt putt issues and dark exhaust emmisions 2 main things spring to mind from my experience. First and most likely is a blocked air filter, even though it may look clean and clear it's probably damp with oil and not letting it breathe. Remove the air filter from the assembly and start and run and see if this rectifies your problem. Second possible cause is a faulty spark plug, replace and check for symptoms.
There is a possible third cause, to do with the pilot jet, but this is unlikely given your symptoms and we'll get into that if the other 2 remedies fail to yeild favorable results.
Give these a try and report back and we'll go from there.

Hey Bigted, thanks for the reply. I did a bit of research on the operation of the carby to understand what happens in there. As I understand it, with the choke basically closed, and the throttle fly open, the air flow will draw a rich fuel mix into inlet manifold. Since I took off the air filter and cleaned that air pilot it has made a big difference, so I think that was my starting issue, which has been solved. When the mower is in the cold start position and is running, should it still be burning a bit of smoke or is the fuel mix not quite right? When I move it to the run position it really is motoring, so maybe that is good enough to leave as is? As to bending the actuation arm for the choke I think I will leave that for the moment, as I think I don't need to worry about it. If anything the fact that it is slightly open should help more air into the ventura. later today I will take off the filter and check that too. I will also check my speed reduction as I go thru the gears, but it seem to me, the throttle fly isn't being turned to reduce air so will also check that too. I take it this fly should open/close for speed control, and I wonder if the spring setting on the governor can be changed to effect this, so will check that too.

Ok, sounds good, do your checks.
Remember, in the cold start position it will cough, splutter, putt etc as the fuel mixture is overly rich and is used as a starting aid only. Once started the throttle should be backed off to disengage choke yet still maintain maximum governed RPM, that what the screw underneath the "choke actuation arm" is for. Just as the governor control hits it it stops resisting the governor and only choke control is engaged from that point onwards with no effect on engine speed. There is no mixture setting on your carby and the small metal adjustment screw on the front is simply an altitutude adjustment for the idle circuit only and will have little effect on idle and no noticable effect at full throttle.
Yes, the butterfly in the carby controls the speed control yet the smallest amount of movement will increase/decrease RPM's significantly. The governors function is to slow down the engines RPM's, the large spring at the bottom, which is not visible in any of your photos, is responible for pulling on the governor arm to increase RPM, so its a bit of a tug of war until a nice equilibrium is reached and a steady RPM is acheived. Maladjustment of the spring and/or governor arm-to-shaft setting can have dire "hunting" results and as such i don't recommend playing around with those settings too much.

Hi Bigted, sorry for the late reply. I checked my air filter situation and it appears ok. I also checked my speed control with the governor/throttle arm fly slowing down RPM. It does move however there isn't much deflection from open to close, so it doesn't really slow down that much, but it does have an effect. Anyway, this all appears as ok now, and I thank you for your assistance.

The only other way to reduce idle speed RPM is to back out the plastic phillips haed screw which sits just above the pilot jet, a very easy adjustment while everything is fully assembled.

Sorry I should have clarified that when I say to slow down the RPM, I mean from the full power and as we go down the speed range till we get to idle speed. Its that transition I was talking about.