Conquest carb jetting

[bluebruin]

This is an educational thread. My guess is black and sooty means running too rich. Were you at highest altitude when you last shut it off?
Pushrods have not slipped out and do not look bent. Engine sure looks clean.

engine does look clean. the guy seemed like he maintained it well enough.

last shut it off at 8,000ft.

I would do a few things first, maybe you have already?

compression test + leakdown test
confirm output of fuel pump (within spec)
If these prove to be okay, I would move on with confidence.

Also, does your machine seem to use any oil or do you notice black smoke under heavy load?

FYI-I would try to avoid backfires on shutdown.

1. do I need special equipment to do a compression test?
2. how do I check fuel output?

does not seem to use oil and have not noticed any black smoke.

The solenoid's actual name is anti-afterfire solenoid. Its purpose is to stop the flow of fuel at the same time that ignition is turned off so that the inertia of the engine doesn't pull fuel/air through the engine as rotation stops and result in an afterfire. You probably won't experience an afterfire anyway but you an mitigate by letting the engine idle and cool a minute or so. Besides, afterfires don't hurt anything.

See THIS EXPLAINATION. (the solenoid purpose fits in the delayed ignition category)

And yeah, I know the pin moves freely. Until it doesn't and plugs you up. When that happens flip the choke on and take your time until you get to the tools and replace the solenoid with a bolt. (or do the snip). (bolt's cleaner )

The spark plug doesn't look all that bad. Maybe a bit lean. Might need the 106 for 8K. (I knew Argo was being conservative with their jetting but didn't have the time to do the experimentation.)

But my reading: The base ring has soot that I would guess means that idle is too rich. The insulator is off white and the electrode doesn't look too rounded so at higher than low idle (the high idle circuit of the carburetor - it has two circuits) it is running somewhere pretty close to where we we want. Do google "reading spark plugs" though as this is not my science.

Your pushrods look good. Like PaSean said, when they are bent they fall out from under the rocker.

You probably need to adjust low idle mixture at higher elevation and you probably need to look at your clutch tuning.

ok. sounds good. I will plug her up. hehe

idle is great at 8k, just not 11k.

Blue try to start the engine, let it warm up some. shut it off and unplug front spark plug wire if it starts and runs that cylinder is firing, shut it off and replace wire and remove rear wire see if it starts and runs.
Or you could remove the valve covers and visually look at the push rods/rocker arms and see if one is off.

The Kaw's don't run that noticeably bad when running on one cylinder except under load
.
It sounds as if it either has thrown a push rod or the fuel solenoid is sticking partially closed ( which would make the jet intake smaller than it is) as Thorn wrote.

Put the plug in the fuel solenoid. Put everything back together.

warmed up engine. unplugged front spark plug wire, tried to start engine. would not start.
plugged back in, started up.
unplugged back spark plug, started up.
unplugged front again, would not start.

maybe I am running on one cylinder? Both sets of exhaust pipes are hot when running (with both sparks plugged in)

[Buzz]

for a compression test you'll need a compression tester. You will crank the engine to obtain a reading. (warmed up engine)

for a leakdown test you'll need a leakdown tester. Instead of cranking the engine, you'll instead use an air supply attached to the tester to pressurize the cylinder and note your percentage of leakage. It will tell you more about where the leakage is taking place (if present)...intake/exhaust valves or piston rings. Also done on a warmed up engine one cyclinder at a time and with the cylinder @ top dead center. Like the compression tester, the leakdown tester is screwed in place of a removed spark plug.

Look up the specs on your fuel pump. Then you want to catch the fuel from the pump over a designated period of time and measure the volume produced. You'll have to look that up to see that it is within specs. Electric pumps just need voltage (usually just the ignition powered on). Mechanical pumps will need your engine cranked at normal cranking speed for a certain length of time. Again, you'll have to look that up.

Look up a couple videos on youtube to help you along. Also make sure your choke isn't closed or partially closed when you don't want/need it. Might be worth checking from end to end (quick and easy).

[bluebruin]

by the way, twice now (once at 11k, once at 8k) I have noticed underpowered performance (difficulty turning or moving) and then suddenly I have a momentary boost, usually right after I changed gears. Maybe one of the cylinders is kicking on and off?

[Buzz]

your ignition coils can most certainly be an intermittent problem. That's where it's frustrating, because even if you confirm spark with the hood off, it can still happen when you go to drive the machine. Forgot to ask, how many hours on your engine?

[bluebruin]

your ignition coils can most certainly be an intermittent problem. That's where it's frustrating, because even if you confirm spark with the hood off, it can still happen when you go to drive the machine. Forgot to ask, how many hours on your engine?

350 hours

[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.