Thanks to a lot of great advice in this forum, I am quite close to calling myself a small engine mechanic. However I still have a giovanni 50 cc mini atv that will not start!

This did not run properly since I bought it last year, but had it working on half choke and parked it that way for winter. When I went to start it this spirng it would not fire.

Here's what I've done so far:
1. Fresh gas.
2. Checked fuel filter--lots of flow to carb.
3. New spark plug--upgraded to NGK. Good spark with either plug.
3. Cleaned carb. It was quite dirty.
4. Adjusted valves. Viewed a handful of videos on youtube to figure out how to do this. I think I did this correctly. However, I'm not 100% sure I was a top dead centre--there are many markings on the top of the fly wheel, but none appear to be a "T".
5. Cleaned carb again. Both jets and Q-tip everywhere (same as previous time).

This doesn't seem to be getting fuel. What next?

Have you taken the jets and the fuel screw out of the carb for the cleaning? You need to be able to see light thru the jets and also thru the holes in the side of the main jet holder. (what the main jet screws into)..

Oh and did you check the float height while you had it apart? Most appear level when the carb is held upside down.

Yes, I cleaned both jets (both times). The float appeared fine (what exactly am I looking for--just that it is level?)

Yes the float just appears level..

Some spray starting fluid in engines at this point...Im not really fond of it so I pull the plug.. drop a few drops of gas in the plug hole.. put the plug back in and try to start it... if it starts or tries to start you will know you dont have fuel coming out of the carb..

I poured some gas into the sparkplug but it still wouldn't fire.

I also switched the carb with the Gio 110 we have and still would not fire. I put the 110 carb back on the 110 and it fired right away.

So it would seem it is getting fuel and getting spark. ???????

Have you measured the engine compression? If it is low then the engine won't start.

You have spark, but did you measure it with the plug outside the engine with the plug held against the engine block? This is the proper procedure of course, but there is a pitfall in this test: The engine spins faster because there is no compression, and sometimes the CDI gets triggered fine at faster cranking speeds, then fails to get triggered when the plug is reinstalled and the engine cranks slower. Take your spare plug and test for spark while the other plug is installed in the engine so it cranks at normal slower speed. Do you still have spark? I've read posts (in another forum a while back) where a quad wouldn't start unless the cranking speed was boosted by jumping the quad to a running car (putting out 14 volts). The cause of the starting problem was the ignition trigger pickup coil outside the flywheel being spaced out too far. Once that quad was running, several more posts came in saying their hard starting problems were fixed also when they tightened the gap bewteen the pickup coil and the flywheel. All the quads were new Giovannis.

I also remember this strange problem posted here a while ago:

http://forums.atvconnection.com/chin...igure-out.html

Normally the ignition timing isn't adjustable and need not be checked, but the above link shows you can't be so complacent.

Strange problem....

I'd measure the compression first.

I don't have a compression tester, but I put my finger over the sparkplug hole and based on this crude mesurement the compession seems fine.

I used the spare plug and checked the spark when the engine was under compression, like you suggested, and spark was good.

I also tried to start by boosting to a running vehicle, but no luck.

I tried again to put some gas down the sparkplug and nothing.....

So, there is fuel and there is spark. Did I screw up the valve adjustment? I'm not exactly sure how this affects things but I'm running out of things to try.

I read the thread that you had linked to. I'm not sure I 100% understand what is being said there. Is he saying that I may be missing a ground wire?

The thumb over the spark plug hole is better than nothing, but not very definitive.

Valve that are a liitle too tight will make an engine hard to start. Valves that are a little too loose are just noisy.

Rather than trying figure out any missing ground wiring I would use a timing light to check the ignition timing. If it is correct than there is no need to delve further. My quad has a rubber plug that can be removed in the side cover over the flywheel that allows an engine timing light to be shown in and illuminate the timing marks on the flywheel.

How would you check the timing using a timing lightÉ First of all, wouldnèt you need to have the engine runningÉ And secondly, doesnèt there need to be numbers to read somewhereÉ Please forgive me if these seem like stupid questions, but this is my first attempt at most of this stuff.

I found this video on youtube: YouTube - How to check valve timin on Honda 50 70 cc motors . Is this how I can check the timing without a timing lightÉ

To use a timing light you only need to have spark, and 12 volts from the battery to power the timing light. The inductive pickup on the spark plug wire triggers the timing light to flash. And of course you have to do this while the engine is cranking.

Yes you need an indicator of some kind. But in this case it is not numbers on a readout, but rather marks on the flywheel lining up (or not lining up as the case may be) to marks on the engine. The "flash" from the timing strobe light visually freezes the marks on the flywheel and engine in time, and allows you see if the electrical spark is happening at the right time or not. There is usually a rubber plug on the engine cover that you can remove to shine the timing light into to strobe the flywheel marks.

I have to say though that having the ignition timing wrong is a long shot at best. In the linked post about this problem note how surprised I was that this could even occur. But if this is what is happening then it has to be addressed.

This is not the same as valve timing. Valve timing has to do with when the valves open and close relative to piston position. I've never worked on your engine, so I don't know if the video you linked to is applicable or not. Perhaps others on the forum can comment.