300 cc Zodiac wont start. By w4wpa (Read 2,786 times)

[w4wpa]

Went to the fuel depot today to fill up tank and as I pulled into the station my motor shut off. I coasted up to the pump and filled up but then it wouldn't start. Came home and got my trailer and went back to get it. Tried several more times to start with no avail. Pushed it into the garage and pulled the plug. (new plug 10 miles ago) Plug was dry and I checked for spark and it appeared to have plenty. Watched the fuel filter (it's new) and cranked the started. Appeared to have fuel flowing into the filter. Pulled fuel line from the carb that comes from the pump and bumped the started and plenty of fuel shot out of the line. Opened the breather and gave a shot of starter fluid into throat of carb and cranked starter. Still nothing. There is only 1 adjustment on this carb and that is throttle adjustment. I see no fuel adjustment for the jets. Any ideas? I've replaced fuel filter, fuel lines, spark plug about 10 miles ago. There is 800 miles on the machine. Any ideas?

[ellpee]

Don't think it would be responsible for a total non-start, but FYI, as far as I know the Zodiac has the same engine as my Magnum, and the F/A mixture screw is on the BOTTOM of the carb, with a plug to keep people from messing with it (California thing, I guess). Even getting at it to remove the plug involves loosening the air and manifold clamps and rotating the carb. If you're gutsy enough, it'd be easier to completely remove the carb. Problem, of course, is that with the carb off you can't make mixture adjustments while the engine is actually running. Catch 22. Once you've removed the plug, you might need to buy or manufacture a very, very short flathead screwdriver that will let you turn the mixture screw with the carb in place and the engine running. Which brings us back to the fact that it won't even start; on that, from your description I have no suggestions -- you've checked everything I would have checked. Hopefully the Big Gurus here will have ideas.

[coji]

I had almost the same thing with the same mileage happen to my DF300TKB. It's motor is the Linhai 300cc. I wish I could say I came up with the solution, but one of the High School kids that I work on their laptops did.

He works on outboard motors, but had a better idea than me. He pulled the air line off the carb and it was blowing back gas into the air filter. This is what the carb looks like on mine, hope yours is similar.

The are just 2 screws to take the top (brass piece) off the carb. Be careful of the spring and don't lose it. There is a rubber diaphragm in there that has a metal pin on the bottom center. It is supposed to be concaved downward, but mine was stuck up, convex.

You can see the diaphragm on the left picture, it is the part under #2. Put this back together aligned up with the rubber seal, and mine at least, worked like a dream afterwards.

Hope this helps some.

[alleyoop]

When you checked for spark where did you ground the spark plug on the frame or motor?

If you getting spark, It sounds like maybe the valves are tight and it is losing compression if it did not even attempt to fire with a shot of starter fluid.
At 800 miles I think it would be the first thing to do is adjust the valves before messing with the carb.
Alleyoop

I believe this is the carb that is on there:

[w4wpa]

I posted a reply to this (I thought) but it must not have posted so here we go again.
I sprayed ether into the throat of the carb again and hit the starter and it fired up and ran well. I've still got a fuel/air mixture setting to take care of as soon as I can get down to the bottom of the carb to remove the adjustment screw cover. Dumb place to put fuel/air screw. I used to rebuild carbs back in the 60's-70's on drag cars and have never seen an adjustment screw in a place like this one.
I always grounded the spark plug against the motor when checking for a spark. I have adjusted the valves about 300 miles when I did my first oil change and went over all of the bolts, nuts etc. I hated to change the oil at 300 because I use synthetic oil and it looked as good coming out as it did going in but to be on the safe side, I changed it and the trans oil just incase there were particles. It's running like a top now. I keep thinking every time I get on it, if I'm going to have to call to have the wife bring me the trailer. I imagine I'll get my confidence back after I put a couple more miles on it. The first 700 miles was no problem and the next hundred, I've had to push it down my street to home after a 70 mile trip then had to load it up in the trailer when I quit on me at the gas station. I really like the scoot and really get a lot of compliments on it but think I am going to wait for awhile before I order one for the wife. (She wants her own trike). I only wish that I would have gone thru Jim when I bought it instead of where I did. Sometimes best price isn't the best.
Coji, thanks for the reply and good pictures of the motor and carb.

[JR]

Wait a minute hold the bus! Did you put synthetic oil in it at only 300 miles or less? And you still have less than 1k miles on it now? I sure hope not because all know that you break a scooter in with dino oil for at least 1k in miles. Many a story has surfaced of unseated rings due to putting synthetic oil in before the engine is broke in.

JR

[w4wpa]

JR, Now that I look back on it, I did used a standard, Havoline, oil in it for the first oil change (15w-30). I had bought synthetic oil for it then figured that for the first 300 miles, I would use regular oil to clean the engine but at 300 miles I changed to synthetic. I had 300 miles on it the first week I had the scoot. I had never heard or saw anything about not using synthetic oil in these engines. With only 500 miles on the synthetic, I can change it back to the regular oil.
In my days of building race engines (mopars) I've always used synthetic oil once it hit the market about 1968
Do you think I should change it out? I don't know much about these Chinese motors.

[ellpee]

Oct 21, 2013 13:29:49 GMT -6 JR said:

Wait a minute hold the bus! Did you put synthetic oil in it at only 300 miles or less? And you still have less than 1k miles on it now? I sure hope not because all know that you break a scooter in with dino oil for at least 1k in miles. Many a story has surfaced of unseated rings due to putting synthetic oil in before the engine is broke in.

JR

I too had never heard/read that. I put synthetic in both my Roketa and my Magnum at about the 300 mile point. Roketa now has ~2700 miles and a total of three oil changes behind it, and the Magnum has ~1000 and is due for a change. No idea what the symptoms would be for "unseated rings" -- don't even know what it means, really -- but both engines seem to be running fine.

[JR]

scooterfocus.com/scooter_break-in.html

It's probably not a good idea to use synthetic oil during the break in period. Good old dino (dinosaur!) oil is probably what you should use. Synthetic oil may be too slippery and not allow the parts (mainly the piston rings) to "bed in" properly. I'd stick with the manufacturer's recommendation (typically 10-30W) until after the break in period of 500-1000 miles. Then you can switch to a synthetic blend if you want to.

I can put article after article here on this subject "bed in" is the same as  seat.


mototuneusa.com/break_in_secrets.htm

3 more words on break- in:
NO SYNTHETIC OIL !!

I'll also tell you from personal experience I put synthetic in my Bali 150 at 1200 miles, in three days I had a leaking engine. Also I'll ask a question, when you change the oil which had you rather do? Throw away $9 a quart oil or $3 a quart oil that does just as good a job? I've got over 12k on my 250B with the linhai and she still runs like a scalded ape. All on Castrol 10W/40W in the winter and 20W/50W in the hot summer.

JR

[w4wpa]

Thanks JR for the info. Point well taken about the discard of the $9 a qt. vs $3 a qt. I will change out the Oil and go to
my Havoline or Casterol.
I've built race motors for years and always used synthetic oil without a problem but then again, the oil was changed out each season
and sometimes 2 times a season and with Amsoil as one of my sponsors, oil was free to me.






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