110cc Loncin engine running rough

[WantToBe]

I have an old quad with a 110cc Loncin engine, with Forward/Reverse gears.

Problem is that it runs rough and it blows some smoke also (it's noticeable but not bellowing smoke). It has spark and 150 PSI compression. I've stripped/cleaned the carbie since the spark plug was building up black carbon deposits quickly.

I am assuming since it has 150psi the timing/etc must be OK. Should I assume that??

Should I buy another carbie to eliminate carbie problem?? When I push the accelerator the revs increase, but the roughness is still present. To me, if it was a 4 cylinder engine I would say 1 of the cylinders was not firing.

Another symptom: it was running, I stopped it. It wouldn't start. No spark. Had to clean the plug to get spark again.

Thanks

[Gwbarm]

It sounds like its running really rich have you tried adjusting the carburetor, or changing the air filter, those are the simple first try things.

[WantToBe]

4 hours ago, Gwbarm said:

changing the air filter

doesn't have one

 

4 hours ago, Gwbarm said:

adjusting the carburetor

I've cleaned another carbie from another old engine, I'll see how that goes

[Gwbarm]

Had to look that engine up. I have never worked on one , should be easy to get that one going, looks like a Briggs clone. Those engines are pretty easy to get going. I work on a lot of Briggs and Kholers. Hopefully the replacement carb works. 110cc that about 8 hp, compression is good.

[WantToBe]

Changed the carbie, still the same. Either I got 2 carbies with the same problem or problem lies somewhere else.

On 6/8/2023 at 9:39 AM, WantToBe said:

I am assuming since it has 150psi the timing/etc must be OK. Should I assume that??

I am still assuming this. Going to search youtube for chinese engine repairs 😉

[Gwbarm]

Sorry to hear that have you checked the coil for proper resistance, may be weak not getting a clean burn. If your timing was off you should be getting a backfire or at least a weird popping sound, not sure on that engine there should be timing marks where you can check that.

[WantToBe]

5 hours ago, Gwbarm said:

checked the coil for proper resistance, may be weak not getting a clean burn.

ok, I thought it either worked or didn't. I'll replace and see.

 

5 hours ago, Gwbarm said:

there should be timing marks where you can check that

there is. I purchased a couple of old quads hoping to get a 'decent' one, but every one I got home has engine problems (you get what you pay for they say). Got 4 other engines (110cc) on the garage floor (not working). I decided to stop buying and try to fix them as best I could. This motor is the starting point; a lot of learning to do I guess.

[Gwbarm]

They can get weak , but I hate to see you spend the money if yours isn't bad, does your quad have a CDI box, I haven't been able to find a service manual for that engine, if you have one it would tell you the  if it has a CDI it should be about .12 OHM on the primary and around 6 on the secondary. If it doesnt have a CDI OHM ratings will be higher.

[Mech]

If you have a timing light you could connect it and see if the spark is regular, or missing a beat every now and then. A misfire will cause a dirt black plug, as will a flooding carb.

If there are breather hoses on the carb, check they are clear and connected to the right place. If it has a vacuum operated fuel tap, or pump, check the vacuum hose for fuel.

If you turn the fuel tap off, does it come right after a few seconds to a minute as he carb empties ?

[WantToBe]

Looks like introduced the problem myself 😔, when I cleaned the carbies I left the needle seat out of both. My inexperience. Installed the needle seat and motor runs fine now.

Thanks for the help guys 👍

[WantToBe]

Note to the moderator: Why are my posts flagged as 

"Your content will need to be approved by a moderator"

Everybody get that OR it's only me??

[Ajmboy]

19 minutes ago, WantToBe said:

Note to the moderator: Why are my posts flagged as 

"Your content will need to be approved by a moderator"

Everybody get that OR it's only me??

First 10 posts are moderated unless you subscribe to a premium membership. This is the avoid spammers and people joining for access to downloads and then bouncing. 

[Gwbarm]

That would certainly do it, im surprised you dindt have gas running out, glad you got it sorted out.

[Mech]

That was a good learning experience then..  haha.

Glad you got it sorted.. and fessed up..  haha..  Onya.

[Gwbarm]

How do you like the quad now that you have it running. Not sure iv ever seen one.

[WantToBe]

19 hours ago, Gwbarm said:

im surprised you dindt have gas running out,

I looked into the carbie whilst the engine was running rough and there was petrol gushing up from the bowl past the needle... I thought then "oh, that's a lot"

 

On 6/10/2023 at 7:54 AM, WantToBe said:

I purchased a couple of old quads hoping to get a 'decent' one, but every one I got home has engine problems

BECAUSE everytime I got them home I thought I'd do the right thing and clean the carbies (the engines ran when I purchased them, the owners started the engines in front of me). That's what I couldn't understand. 

The key thing was, I'd see a bronze cylinder (maybe 8mm long) on the floor/work bench when I was cleaning up after the carbie strip/clean. Couldn't figure out where it come from. I had 2 of them sitting on my computer table for months, just in case they were important. Finally, I watched some videos on youtube and one guy stripped down a carbie and I could see these same bronze cylinders. I felt like I won the lottery!!!  In this carbie there are 3 components in the metering process (not including the needle): the main jet (which has a number on it), the needle jet holder and the main jet (this is the 8mm cylinder). Youtube guy said you usually find these main jets on the floor afterwards ROFFL. They usually fall out when you're not looking and you don't know about them.

3 hours ago, Gwbarm said:

How do you like the quad now that you have it running

One rear tire is flat so cannot go far, just around the suburban back yard but it's good to see the engine running

[Gwbarm]

Glad you got it figured out, you have worked hard on it. Just look at it this way, that's one you won't forget next time, we all make mistakes , that's just part of the fun, right, I have learned to just laugh and tell myself , what a stupid thing to do. 

I have fixed flats with slime, but its not cheap, it may work for a while, the last one I fixed is leaking down again, the best way is to put a tube in it , but you have to take the tire off the rim to put it in correctly, so that means tire tools, I have been taking mine to places that put them on, I don't really like messing with tires, that's a strong statement for me, because I pride myself on doing everything for myself. 

[WantToBe]

I had a flat on a new quad. You see videos of guys spraying gas into the tyre/hub and then use a flame to ignite it, that's not for me. What I do is using a ratchet tie-down strap, wrap it around the center of the tyre and tighten it. What this does is squashes the tire in the middle and forces the tyre steel rims onto the hub. Just add air and your good to go. The only WARNING is just add enough air so the tyre is seated and then slowly release the ratchet - being careful to stand at the side of the wheel so that if the ratchet flies off you're not in the path.

Problem with my flat tyre is that it's old and warn and using the strap technique the tyre will not extend to the hub. 

Was going to put one of the front tyres on the back but it's a different hub. Back hub has 70mm between stud holes and the front hub has 80mm between stud holes. Nothing is easy...

[Gwbarm]

I have done that a few times with starting fluid, not the safest way to seat a tire on the rim , but it works. I think the last time I did it sprayed too much and the tire caught on fire. I have done the tie down and that works sometimes. 

[Mech]

I thought getting quad tyres off was the mission..  never had trouble getting them to go back on.  I just push them down onto one side of the rim, then lift the tyre enough that it closes the gap at the top while I inflate it.. Old distorted tyres though.. yeah sometimes a rope around the circumference works, if it's tightened just the right amount.

Slime..  I love it. We have lots of scottish gorse here, it grows like a weed and huge and drops prickles that will go through a quad tyre. I got sick of fixing slow leaks years ago and fill every tyre with slime these days as a preventative..  in my new tubes even.