motor misses starting at 54 mph By w4wpa (Read 1,021 times)

[w4wpa]

I've got a 300 Zodiac and it has been running great until today. At 54 mph it starts to miss. I've got 700 miles on the engine. Any ideas?

[alleyoop]

Miss or bog big difference.
Try this Bring it up to where it starts to act up and BACK OFF THE THROTTLE about 1/4 of an INCH and HOLD THE THROTTE there.
Pay Close attention to what the motor does:
A. Does the Trike speed up?
B. Does the Trike Just settles down?
Alleyoop

[alleyoop]

If it POPS giving it THROTTLE it is TO RICH, did you by chance change the main jet?

If not Turn the Fuel Ratio Mixture Screw CLOCKWISE try 1 full turn and see if that helps.
Alleyoop

[w4wpa]

The motor misses. It doesn't bog down. I can hold it at 53-54 mph speed and it will pop and miss fire every few seconds. If I back off a few mph, it runs good. It also runs good as long as I don't try to increase the speed with a quick twist of the throttle. If I give it a quick twist, it will misfire while it under load but then will smooth out if I keep throttle constant.

I haven't changed the jet. Haven't changed anything on the carb. I'll give the fuel/air mix an adjustment and see if that helps.

I'm new to this forum stuff. How do you post picture as you have with your scoot?

[alleyoop]

Of course it is going to miss the Plug is getting flooded, BUT the sound it makes is the important thing. Here are sounds a motor makes and each one tells you what the motor needs:
Alleyoop

Different sounds a motor makes tells you what it needs, so listen for any sounds the motor makes.

1. Popping while accelerating is a RICH condition.
2. Popping while de-celerating is a LEAN condition.
3. Burp Sounds accelerating is a LEAN condition
4. Backfires are a Lean condition.

Possible causes for above and fixes:
1. Here the problem is it is running OVERLEY rich the main jet could be to big, or you can try Leaning out the Fuel Ratio Mixture.
2. Here couple things:
a. You can richen up the Fuel Ratio Mixture
b. Idling to low Bring up the idle a little
3. You can richen up the Fuel Ratio Mixture
4. Usually caused by it Leaking where the Pipe Connects to the motor. Bad air leaks cause the backfiring many think it is because it is to RICH but it is the OPPOSITE sucking in air causing very Lean condition and this can damage your exhaust valve.


If it just BOGS on you or starts dropping rpms or bucks but makes no distinguishing sounds then the good old Trick of the Trade will tell you what the motor needs:

TRICK OF THE TRADE:
Lets find out which situation(LEAN OR RICH) is causing the problem.
Run the sucker like you do when it STARTS TO ACT UP Back off the THROTTLE about 1/4 OF AN INCH and HOLD IT THERE:
A. If the scoot Speeds up it is running LEAN.
B. If the scoot Sputters or whatever BUT settles down it is running RICH.

This way you will know what it needs(more or less juice).

[ellpee]

Are you at high altitude? My Magnum, same engine I presume, didn't like running at 7500', way too rich, spark plug would crud up within 50 miles, and eventually to the point it would stall completely and no longer start. All the cranking in the world on the fuel/air mixture screw was still not enough. Changing jets was the trick. May not apply in your situation.

[w4wpa]

Not at high altitude. 5 ft above sea here in Florida.
Thanks Allyoop for the advice. I'm going to replace the plug on it then will try the tricks of the trade. I have backed off a touch and it maintains speed with no miss or pop if I keep the speed at 50 mph.
Another question! Any particular procedure in adjusting shift linkage? I don't like the way it jumps into gear when shifting into gear then accelerating

Did you also see my question about posting a pix as you have on your postings?

[Barnie]

W4wpa,,good looking trike. Double check your air intake system and make sure its not restricting any flow of air to engine. You may also have a tad bit of dirt in the main/hi speed jet. Try running some Seafoam thru it. Barnie

[w4wpa]

I'll do that Barnie. Thanks. I'm originally from Akron, Oh but now residing here in N.E. Fl