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Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 29857
Experience:  Service manager and technician for all brands of engines with 40 + years of experience.
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I have a Castlegarden sit on mower, TCP102Hydro,With a Briggs

Customer Question

I have a Castlegarden sit on mower, TCP102Hydro,With a Briggs & Statton15.5hp twin cyl engine.
My problem is that after about 30mins working the engine breaks down while under drive,
If I release the forward drive pedal the engine revs immediately picks up to full revs and runs freely, as soon as I press the drive pedal it breaks down again, I have to stop and let the machine cool down. It will start and carry on working until it get hot again and the same thing happens. I have changed the engine oil & filter, drained the petrol tank and changed the inline fuel filter,refilled tank with fresh petrol. i have changed the air filter and pre-filter and even replaced the two coils c/w leads, and changed the spark plugs . The engine starts and runs perfectly whilst stationary and not under load. this fault only happens while hot and under load. i.e. cutting grass.
Is there any electrical sensors on the Hydrodrive unit as it only happens when I try to move off.
Submitted: 2 years ago.
Category: Small Engine
Expert:  Curtis B. replied 2 years ago.
What is the model number from engine? Example(###) ###-####B1
Expert:  Curtis B. replied 2 years ago.
I suspect you have a coil that is dropping out. Will work cold, but drops out hot.
Customer: replied 2 years ago.

Good afternoon Curtis,

The Model Series 405777

The type 0113 E1

Code 990202 YG.

I thought it might be a coil breaking down thats why I changed both of them for the new modified type. But the exact problem still occurs.

Expert:  Curtis B. replied 2 years ago.
Twin Briggs, how many hours? Have you checked the valves? .004 to .006 intake and exhaust.
Customer: replied 2 years ago.

Hi Curtis.

I have checked the hour meter and it reads 271 hours.

I will check the tappet clearances tomorrow and give it another road test to see if that makes any improvement.

Apart from the grass box full warning switch, is there any other sensors on this tractor, what about low oil pressure, I've noticed there is a oil pressure switch fitted to this engine but no wire attached to it, there is no warning light on the instrument panel ether.

I have watched on Utube the stripping down of the Hydrostatic drive unit

and cannot see that there can be any connection to the breaking down under load symptoms that I have.

Even thought I have changed both coil units, do you think one could be faulty, it would be very un-likely of this, don't you think.

Expert:  Curtis B. replied 2 years ago.
It would not be a safety switch. But it can be valves !
Customer: replied 2 years ago.

Hi Curtis.

I have looked at the valve clearances, and they were not drastically out, the inlets were okay, the exhaust were a little slack not excessively though. I also checked the vacuum pipe to the petrol pump while I had the rocker cover off, that was fine as well.

I have adjusted the tappet clearances to .005" and put every thing back.

The engine started and runs fine. But I couldn't go out and work the the mower as its poring with rain here. Hopefully I can test it out tomorrow.

Expert:  Curtis B. replied 2 years ago.
Remove the solenoid in the bottom on the carburetor and plug the hole and test.
Customer: replied 2 years ago.

I was looking at that today and wondered what its purpose was, does it cut the fuel flow off when the ignition switch is turned off.

Expert:  Curtis B. replied 2 years ago.
It is anti-backfire solenoid. And plugs the main jet when key is off.
Customer: replied 2 years ago.

When the engine breaks down when it hot, when I joggle the drive pedal to try and nurse the tractor back to the garage, it do pop and backfire.

Expert:  Curtis B. replied 2 years ago.
quick test is to remove it and plug the hole for test!
Customer: replied 2 years ago.

I will go for a test mow tomorrow if the weather lets me, If the engine breaks down as usual I will then remove the solenoid and plug the hole and do a further test.

Its got to be something electrical or fuel, if it was mechanical it wouldn't come and go,

I haven't taken the fuel pump apart yet,

Expert:  Curtis B. replied 2 years ago.
Fuel pump is pulse pump and not likely problem.