Conquest carb jetting

[JohnF]

These Kawasakis will run really well on once cylinder and can fool a guys ear. The unplug/plug certainly sounds like an ignition problem and your other symptoms match up too. Especially now that we have eliminated elevation as a variable.

I had that happen to me once. I was jiggling and wiggling wires trying to see if something was loose and it started working again. I couldn't reproduce the problem after that.

[bluebruin]

When I took off my valve covers, 1 pushrod was off of the rocker. The reason was a very tight valve that the spring tension couldn't overcome and resulted in the pushrod falling out of place. it wasn't bent, but the valve was hanging open a little and my engine had very low power. Depending on how old that spark plug is, the black residue looks like a bit of oil and since the electrode and electrode porcelain are so clean, I'd say it's been lean and maybe running a little hot because of being lean. A proper fuel ratio should show up on a spark plug with sort of a gray or brown color on the porcelain. I'd also double check that the correct spark plugs are in your engine, wrong heat range can cause issues too.

The plugs in the engine are NGK BMR2A. I was noticing the guide says BMR4A. According to the NGK website:

Air (atmospheric) pressure and cylinder pressure decrease as altitude increases. As a result, spark plug tip temperature will also decrease.
Fouling can occur more easily if the air-fuel mixture is not adjusted to compensate for the altitude. Higher altitude = less air = less fuel.

The spark plug heat range has no relationship to the electrical energy transferred through the spark plug. The heat range of a spark plug is the range in which the plug works well thermally. The heat rating of each NGK spark plug is indicated by a number; lower numbers indicate a hotter type, higher numbers indicate a colder type.

I ordered some based on the manual's suggestion of BMR4A before I saw the 2A that was in the machine. guess I'll try those and see how they run.

[bluebruin]

These Kawasakis will run really well on once cylinder and can fool a guys ear. The unplug/plug certainly sounds like an ignition problem and your other symptoms match up too. Especially now that we have eliminated elevation as a variable.

I had that happen to me once. I was jiggling and wiggling wires trying to see if something was loose and it started working again. I couldn't reproduce the problem after that.

well, with mine its mostly NOT working, with intermittent spurts of power, so hopefully I'll be able to tell right away if they are both working again. I will try new plugs first, they are cheap. What other things should I start checking after that if plugs are not the issue?

[PaSean]

bluebruin

The spark plug heat range has no relationship to the electrical energy transferred through the spark plug. The heat range of a spark plug is the range in which the plug works well thermally. The heat rating of each NGK spark plug is indicated by a number; lower numbers indicate a hotter type, higher numbers indicate a colder type.

That is true, the heat range is simply how quickly the plug can dissipate or retain heat that's appropriate for a given application. A plug that's too cold for an engine will foul more easily, one that's too hot can cause detonation, (ping) and or power loss. I'll admit, I was an automotive tech for a few decades and I know modern ignition systems can operate at 50,000 volts plus but I don't know what these little engines are designed to operate at which may make using the correct plug more critical. The wrong plug with a gap too wide requires more voltage to produce a nice blue spark for proper combustion. I've been surprised more that once how the correct plug and gap makes a night and day difference but the plugs could just be one of a few problems.

[ARGOJIM]

You may also check for corrosion at the cdi plugs (black box), they are hard to play with.

Check plugs first, easy, simple, common and more likely. More common with other brands, but happens.

Once on an older machine we had issues with the larger plug cutting in and out from corrosion, it was however completely cutting out. This sounds more like a possible corrosion problem at the black box or dirty flywheel magnets/pick up if the plugs are not fouled.

[bluebruin]

so THAT's what the argo is supposed to drive like! My spark plugs came in the mail today. wow, what a difference. I am ordering a second set right away to keep as spares. Even at 11k, it seems I'll have enough power. Guess we'll find out on my next trip. Can't wait to try it out again. THANK YOU ALL so much for your help solving this. I'll see about clutching etc after trying it at 11k again.

[bluebruin]

by the way, I repeated the start up test with each plug disconnected. It fired right up and ran fine on either cylinder alone. definitely sounds a bit "rougher" on one cylinder now that I can see the difference.

plenty of turning power now. cruises right up the hill, or even a little 2ft ledge at my house at 8k with ease.

[PaSean]

It's great when they operate at full power, now it's time for some fun!

[bluebruin]

my problem is back. I ran the argo hard about 10-15 minutes at my house in the driveway. It was kicking a$$ and a ton of fun. Then, I slowed down, let it idle a minute and when I stared up, no power again. I assume one of the sparkplugs fouled? Can that happen in 15 minutes with a number 104 jet at 8200ft? Looked up on the internet, found this

Since you have new plugs and wires you may have a bad coil. Of course one of the new parts may be bad, not unheard of but unlikely. You need to see if that cylinder is getting spark. You will want to do this test while the engine is hot. It isn't uncommon for coils to work for a short time then fail when it gets hot.

I also read
The number one spark plug failure is caused by oil getting to the spark-plug through piston blow-by - this can be fixed with new rings / pistons (oversize for best performance).

The main cause of bad spark plugs is exactly what i stated above - OIL - now it could be that the spark plug isn't getting enough voltage to make a very hot spark in which case you could look at replacing the rotary cap, coil, generator, etc..

CAUSES OF SPARK PLUG FOULING

If your spark plugs are fouling and keep fouling out, you probably have an engine problem. Normal spark plug deposits are typically light tan or brown in color. Black deposits or heavy ash deposits usually indicates trouble. Some common causes of spark plug fouling include:

Worn or damaged valve guides or valve guide seals. Problems here can allow oil to dribble down the valve stems and enter the combustion chamber. Oil will form heavy black wet oily deposits on the spark plugs.

Worn or damaged piston rings, or worn or damaged engine cylinders. Badly worn piston rings, broken or cracked piston rings, grooves or scoring in the cylinder walls, or even piston rings that have been installed upside down can allow oil to get into the combustion chamber and foul the spark plugs.

Rich fuel mixture. This will produce black fluffy deposits on the spark plugs. If only one or two spark plugs are affected, the underlying cause may be a leaky fuel injector. If all of the spark plugs show heavy dry carbon fouling, the rich fuel mixture may be caused by too much fuel pressure (check for a defective fuel pressure regulator or a plugged fuel return line). A defective oxygen sensor that reads lean all the time can also make the fuel mixture run rich. Check fuel trim readings with a scan tool to see if the engine is running rich (negative fuel trim numbers that are -8 to -10 or more would tell you the engine is running rich). On an older carbureted engine, a rich fuel mixture can be caused by a leaky float, incorrect float setting inside the fuel bowl, a leaky fuel inlet needle valve, or incorrect jetting (too large).

I have messed with both plugs. Here is what I am finding. You can only start on one plug if the front plug is in and back is out. (or you can start on two plugs). Rear plug does not start the argo. Tested the rear cable with screw driver, and I can get spark on the rear plug cable, but it seemed weak to me. So, I tried pulling the plugs independently with the engine running. It will continue to idle with either plug out, but there is a significant difference in engine power/sound/speed while the front plug is in. With only the rear plug in, it almost dies, but does continue to run. When you get the front plug even near the spark plug, you see and hear the spark jumping to the plug. In the rear, that does not happen at all. I think the spark plugs are fine, but I am not generating enough spark energy in the rear plug to cause combustion.

The kawasaki engine manual says you need a "kawasake hand tester special tool number 57001-1394" ignition coils or pulser coils.

anyway have any ideas what would be causing weak spark or what I should test or replace next? Thanks

some suggestions from other threads

Start it up and run it till it stalls, check for spark and check compression. Could be the magnetron getting hot and losing spark, compression could be weak when hot.

I had a 2 stroke that did that and it turned out the rings were shot and the one piston was burned.

thinking back to when I had it up at my cabin, this is the same thing that happened up there. The time it did run with a bit of power, was right after it sat for a while and I first started it up. It ran for 1 minute, and when it got hot, no compression.

[Nubs]

Well if does loose compression only when its hot I would say a valve is set to tight.

[PaSean]

Try moving the front plug to the back and back to the front and see if it will start on the one cylinder then. If it will, it's probably a bad/fouled plug. It's true about getting a bad plug new out of the box but I've screwed in many hundreds of plugs and would venture to say out of them all I may have had 10 that were defective.

[JohnF]

Well, it is cool that you've experienced the running-on-one-cylinder right next to firing-on-all-cylinders so you have a good feel for the difference.

I was hoping your problem was fixed but didn't say anything before because I know that switching from BMR2A to BMR4A wouldn't/didn't fix the problem. In fact, I would guess that the hotter plug was installed to deal with fouling due to rich idle at elevation.

I was hoping that the process of changing the spark plugs fixed the problem. Something like not having the wire clipped onto the plug or something. Right now I am thinking maybe the spark plug wire has a break (just assuming that you didn't jiggle something else). So fire it up and start wiggling the spark plug wire for the cylinder that isn't firing to see if you can get it firing again.

[ARGOJIM]

Well, it is cool that you've experienced the running-on-one-cylinder right next to firing-on-all-cylinders so you have a good feel for the difference.

I was hoping your problem was fixed but didn't say anything before because I know that switching from BMR2A to BMR4A wouldn't/didn't fix the problem. In fact, I would guess that the hotter plug was installed to deal with fouling due to rich idle at elevation.

I was hoping that the process of changing the spark plugs fixed the problem. Something like not having the wire clipped onto the plug or something. Right now I am thinking maybe the spark plug wire has a break (just assuming that you didn't jiggle something else). So fire it up and start wiggling the spark plug wire for the cylinder that isn't firing to see if you can get it firing again.

Caution; You may experience a good tingle if the wire is bad.

[bluebruin]

yeah, I experienced the tingle a few times yesterday I switched the spark plugs front to back as suggested, still no strong spark at back cylinder. I doubt I jiggled anything else loose, I will inspect the cable as best a possible, its hard to see back there.

[bluebruin]

Well, it is cool that you've experienced the running-on-one-cylinder right next to firing-on-all-cylinders so you have a good feel for the difference.

I was hoping your problem was fixed but didn't say anything before because I know that switching from BMR2A to BMR4A wouldn't/didn't fix the problem. In fact, I would guess that the hotter plug was installed to deal with fouling due to rich idle at elevation.

I was hoping that the process of changing the spark plugs fixed the problem. Something like not having the wire clipped onto the plug or something. Right now I am thinking maybe the spark plug wire has a break (just assuming that you didn't jiggle something else). So fire it up and start wiggling the spark plug wire for the cylinder that isn't firing to see if you can get it firing again.

since I switched the plugs back and forth and the problem is consistent, and the front cylinder fires with good spark on either spark plug, I can say the plugs are not fouled, neither the BMR2A nor the BMR4A. It seems to be weak spark in the back. what are the possible causes of that besides a cracked cable?