cub cadet rzt50 keeps stallinn

[ncb1038]

hello everyone i have a cub cadet rzt 50 with a briggs and stratton engine on it. The model for the machine is 17ba5a7p709.

the big issue i have so far is its hard to sstart, if i am able to get it running it may run up to about half to three quarter throttle before bogging out.

a little back story.

so far i have overhauled all the basic tune up items i can think of. The unit has new fuel lines and air filter. A new carburetor (old one was severely gunked up) all gaskets have been swapped during carburetor changeout. new plugs new air filter and oil is bew as is filter for oil. Gas has been drained from tank and has fresh gas only 2 to 3 days old.
battery is good and holding a charge with no issues. Although i have had to trickle charge it a few times due to struggling to get functional operations out of the machine.

Things ive checked since the plugs after swapping everything keep indicating the system is rich in fuel and i have even seen fuel misting towards the air filter housing when its running. The fuel solenoid appears to be functioning as i hear the audible click each time of the solenoid operation. Ive looked over the throttle and choke lines to inspect if anything was getting caught but operation is smooth.

Any input is greatly appreciated and if any more information is needed let me know i have a multimeter and can get readings more accurately if needed.

 

[Gary62]

I would check and double check the carb to make sure it's the right one and is adjusted correctly.

 

[ncb1038]

I would check and double check the carb to make sure it's the right one and is adjusted correctly.

I thought the same but with the cub cadet ther version of the carb they use isnt adjustable as far as i can tell. I see no mix screws only available adjustment i can make is idle screw. As for correct carb i looked up the part in the manual and ordered it from amazon. It matches what came off but whos to say everything is a perfect match

 

[bertsmobile1]

Adjust the valve lash and make sure that the choke closes fully, if not undo the cable clamp & adjust the position.

 

[ncb1038]

Adjust the valve lash and make sure that the choke closes fully, if not undo the cable clamp & adjust the position.

On point with valves since i had time i pulled the left cover to begin checking and found the push rod bent for exhaust valve. Attempted to adjust it but then found that the valves were stuck. Ended up pulling the head off and found both valves stuck open due to carbon buildup ive managed to free them now i got to due some cleaning after i remove the springs and pins retaining the valves. The valves dont appear bent at first glance but ill know better once i open the pin and springs. The mower sat for many months before attempting all the work. Got it with the home i purchased. Been tunking because aside from the running problems its still in decent shape and only has 400 hours logged in the timer

 

[bertsmobile1]

Surprised it started at all
But a good , if not slightly costly result .
Measure the amount the valve guides protrude into the head
They should all be identical inlet & exhaust left & right
With stuck valves good chance the guides shifted before the pushrod bent .

 

[ncb1038]

Surprised it started at all
But a good , if not slightly costly result .
Measure the amount the valve guides protrude into the head
They should all be identical inlet & exhaust left & right
With stuck valves good chance the guides shifted before the pushrod bent .

The good news today on the situation. Cylinder 1 was the one gunked up. Cylinder 2 had no issues and could get the mower started but with the lack of valve operations due to gunk and as you stated bent push rods in cylinder 1 valve head cause the rich operations and stalling.

I pulled the head and. And removed spring yesterday and soaked it over night the valves themselves came out with a small amount of persuasion ( spun them in place and pulled at the same time) after that cleaned the head and valves. Replaced head gasket. And reassembled the valves and new push rods. And then reassembled the whole thing. It fired right up after re assembly and i even made it through half an acre (live on a 1 acre property but got rained out during testing) with no operations issue seems like the culprit i can surmise is lack of maintenance led to carbon buildup, not too serious an issue but the time since i bought the home and began working on it has been almost a year i believe the buildup froze everything in place.

At least after the last month of trying to revive the mower left behind i am proud to say its running smooth

 

[bertsmobile1]

You might like to think about going one grade heavier oil
The oil could be thinning just a little too much thus building up excesively inside the cylinder .

 

[ncb1038]

You might like to think about going one grade heavier oil
The oil could be thinning just a little too much thus building up excesively inside the cylinder .

Thanks ill do it next oil change