Hard starting looper with bad cold idle

[JasonB]

On a ‘94 Johnson v4 looper- tracking a cold hard start condition, excessive smoke at startup, and lean sneeze. Started suddenly late last year. Runs perfect at speed. Compression is ~118-120 across all.

Hadn’t cleaned the carbs in a few seasons, so Rebuilt carbs this spring with OEM kits after cleaning with an untrasonic cleaner, checked that the bowls are flat, floats level with the lip of the bowl.

Haven’t checked the record valves themselves, but the hoses seem ok with no appatent leaks testing with carb spray and propane.

Had an indicator of a possible leak in the intake to manifold gaskets, so replaced them.

Idle in the flusher won’t drop below 1200, it coughs and sneezes, with. Excess smoke. In the water is better, but still not right.

Starting to look at other possibilities and exploring the QuickStart circuit. If I probe the white/black wire on the power pack with it disconnected from the temp sender, I get a short to ground. It’s my understanding this should be open and the temp sender supplies the ground to exit QuickStart. Is that right?

 

[racerone]

Checked the flywheel key?-----Check operation of the electric primer valve?

 

[JasonB]

Checked the flywheel key?-----Check operation of the electric primer valve?

I’ll add those to my list to check.

 

[saltchuckmatt]

On a ‘94 Johnson v4 looper- tracking a cold hard start condition, excessive smoke at startup, and lean sneeze. Started suddenly late last year. Runs perfect at speed. Compression is ~118-120 across all.

Hadn’t cleaned the carbs in a few seasons, so Rebuilt carbs this spring with OEM kits after cleaning with an untrasonic cleaner, checked that the bowls are flat, floats level with the lip of the bowl.

Haven’t checked the record valves themselves, but the hoses seem ok with no appatent leaks testing with carb spray and propane.

Had an indicator of a possible leak in the intake to manifold gaskets, so replaced them.

Idle in the flusher won’t drop below 1200, it coughs and sneezes, with. Excess smoke. In the water is better, but still not right.

Starting to look at other possibilities and exploring the QuickStart circuit. If I probe the white/black wire on the power pack with it disconnected from the temp sender, I get a short to ground. It’s my understanding this should be open and the temp sender supplies the ground to exit QuickStart. Is that right?

Here's how I think it goes and others can confirm. Quickstart starts closing at 105 degrees or so...so I suspect that maybe remains open...the tan wire closes when it overheats so that's definitely grounded.

Those two wire sensors are hard to find and expensive...best to go to a one wire from what I understand.

Others may disagree.

 

[saltchuckmatt]

Just caught up on my manual, first wire closes to ground at 96 degrees to shut down quickstart.

 

[JasonB]

Here's how I think it goes and others can confirm. Quickstart starts closing at 105 degrees or so...so I suspect that maybe remains open...the tan wire closes when it overheats so that's definitely grounded.

Those two wire sensors are hard to find and expensive...best to go to a one wire from what I understand.

Others may disagree.

The port sensor with 2 wires is NLA new. I found the tan wire has come unsoldered from the sensor, so I’ll have to address that somehow, maybe strip the wire back and use some conductive glue so I don’t hose the sensor itself with heat from a solder.

That said, I think the tan wire is only the overheat alarm.

White/black wire seems ok, but I’ll test it warm to make sure it closes.

 

[JasonB]

Following up on this one. After doing some reading and getting more clear on what to look for, I found tat at least 2 carb bowls were warped. I’ve now replaced all 4, using new bowl and base gaskets. I double checked and adjusted the floats.

It now “idles” much more evenly, but at 1700ish rpm. I put a timing light on cup 1 and it’s firing at 4deg ATDC.

I pulled the #1 plug and did the screwdriver test to check alignment on the flywheel and it appears TDC is right where the piston stops, so hopefully not a sheared key.

Also made sure nothing appears to be interfering with the timer arm.

I retested the QuickStart circuit and without the sensor connected, the white/black wire shows about 1300 ohm to ground, so seems that’s likely ok.

I don’t know how to check the lower crank seal outside of spraying carb clearer around the base, which made no difference.

Before fixing the bowls, it was idling at 1400-1600 with lots of sneezing, now we’re at 16-1700 with almost no hiccups.

The motor has sneezed for the 8ish years I’ve had it, getting much worse at then of last season. Maybe someone have messed with the timing before I got it to try to get it to idle better and now that the carbs are right, it’s out of kilter?

Could this be a case of the idle timing being wrong?

Attaching photo of how things sit. I haven’t mucked with the timing settings in the time I’ve had it.