Kawasaki FC290v-as02 -Deere SX75

[Mikep0317]

Good morning
I am working on an older Deere SX75 with the FC290V Kawasaki motor

While cranking my compression gauge shows 125# but as soon as I turn off the key the compression drops to zero
If the use starting fluid I can get the motor to start and run but it will not start without the starter fluid
I checked the head gasket (looks ok), set valves (4 & 5/1000)

Installed aftermarket carb - made no difference really

Cranking the motor without starter fluid seems to generate some backfire / misfire thru the carburetor also

It will run and idle fine, just does not seem to be able to draw fuel on its own

Is this normal for compression to drop as soon as the stater stops cranking the motor?

Any direction would be appreciated
TIA

 

[Oddjob]

Good morning
I am working on an older Deere SX75 with the FC290V Kawasaki motor

While cranking my compression gauge shows 125# but as soon as I turn off the key the compression drops to zero
If the use starting fluid I can get the motor to start and run but it will not start without the starter fluid
I checked the head gasket (looks ok), set valves (4 & 5/1000)

Installed aftermarket carb - made no difference really

Cranking the motor without starter fluid seems to generate some backfire / misfire thru the carburetor also

It will run and idle fine, just does not seem to be able to draw fuel on its own

Is this normal for compression to drop as soon as the stater stops cranking the motor?

Any direction would be appreciated
TIA

I have the same engine on my RX-75 and exactly the same issue. To cut to the chase, I have never solved it but here are the things I considered. This is a gravity fed fuel system so make sure you have the right fuel filter. A filter designed for a pressurized fuel system doesn’t allow enough fuel to get to the carb. Fill the tank to the top and see if the increased pressure helps with your cold start. Make sure that the choke is fully closing. I hope someone chimes in here with better ideas. But I’ll tell you what I did to make my life easier. I drilled a hole in the air filter cover just big enough to accommodate the straw on a can of carb cleaner. I did this underneath the large flat washer that goes on top of the knob that holds the filter housing down. This ensures there is no unfiltered route for air to take into the carb. This eliminates having to take the whole housing off and then having to reassemble with the engine running. Just spin the plastic knob off, remove the washer, spray your carb cleaner or starting fluid, start the engine, replace washer and knob.

 

[StarTech]

Defective compression gauge. They are suppose to have a check valve ie valve stem core.

And sounds like the choke is not fully closing.

 

[slomo]

So it will run with starting fluid. I would look for a clogged pilot jet or circuit.

Also could be debris in the fuel tank and tank outlet barb/nipple.

Fuel lines deteriorate internally so you will not see bad lines. Just replace them all from tank to carb.

It will run and idle fine, just does not seem to be able to draw fuel on its own

If it runs she is drawing fuel.

Installed aftermarket carb - made no difference really

Entire carb needs to be gone over. New is not new these days especially for mower parts.