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it will start when cold most of the time but when warmed up it sometimes is very hard to restart has a Kohler kt-715 on it any ideas would be helpful...

James

Fuel tank spotless, like a new one? Zero restriction on the outlet?

Solid fuel flow AT the carb inlet? Drain into a glass jar. Inspect for water in the bottom.

Cooling fins cleaned yearly or more often?

Valve clearance inspected recently as in yearly meaning every year?

Strong spark once engine is hot? Not using a Christmas light spark tester either. Something that will stress the coil into throwing maximum spark. Like the below.

thank you for your reply.. was able to go by my dad's place today he lives about an hour and a half away .. took the front cover off very clean checked the connections on the ignition coils.. we drained the fuel tank replaced both the fuel filter and fuel pump.. was good flow at the pump outlet to carburetor.. .. watched him cut grass about twenty minutes into cutting it started to make a popping sound motor lost power sounded to me like unburned gas in the muffler.. then ran good until he finished.. still hard to start when hot.. any ideas??

Hello bear369,

toro zero turn 76601? You gave us minimal information to work with. The product label numbers and the engine label numbers are very important. It reduces assumptions and confusion for the folks out here trying to assist you.​

Otherwise, we are left to "spitball" some answers and see if anything sticks.

I have seen spark plugs do some strange things like this in the past. Resistor style plugs are prone to develop some cracks internally. Never trust spark plugs from Amazon, too many defective cheap copycats.

Have you tried using the choke briefly during a hot restart? Sometimes that helps. With age and wear, they can tend to need the choke at every start regardless of being cold or hot.

bear369 said:

unburned gas in the muffler

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Pressure test the carb needle at 7psi for 30 minutes. Your needle sounds intermittent.

thank you for your reply's... the motor is a Kohler kt 915- 3098 dad uses it daily to go back and forth to his barn he has a small cattle operation when not cutting grass with it... he has tried chocking the motor when staring when hot.. no difference the engine shroud and colling fins had very little grass trimming .. we used an air compressor to remove what was inside it...

bear369 said:

thank you for your reply's... the motor is a Kohler kt 915- 3098 dad uses it daily to go back and forth to his barn he has a small cattle operation when not cutting grass with it... he has tried chocking the motor when staring when hot.. no difference the engine shroud and colling fins had very little grass trimming .. we used an air compressor to remove what was inside it...

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Your model and spec don't exist per Kohler.

Using just the spec number Kohler comes up with for KT is KT735 and KT745. No KT715 or KT915.

slomo said:

Pressure test the carb needle at 7psi for 30 minutes. Your needle sound intermittent.

Click to expand...

Hi slomo,

Can you elaborate how you do this?

Auto Doc's said:

Hi slomo,

Can you elaborate how you do this?

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With a pressure/vac tester and the carb inverted. Like my Mityvac 8500

Hi slomo and StarTech,

Thanks for uploading examples. Many of our followers are not aware of these strange testing methods that are used to verify carburetor needle a set sealing effectiveness.

dad emailed me today.. it is a KT 715-3098 we have cleaned the shroud and cooling fins of all grass clipping.. but very little debris under the engine cover.. thanks for your help..

Something us wrong here as the KT715 is a 20 hp engine and Toro says the mower is suppose to have a 26hp which is the KT745.

What is the engine's serial number? I can use that to get Kohler to look it up.