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Lifted front now won't start

#1

JamesD

JamesD

The mower is a 42 inch poulan pro automatic with a briggs and stratton 17hp intek motor.
Mower PN: pr17h42sta

Mower was running fine last time I cut the grass.

After sitting about a week, I found that grass had built up under the mower deck so rather than removing the deck to clean it I just lifted the front end of the mower until the wheels were about shoulder height. I braced it there with a board and scraped the deck to remove the large chunks of grass. I then spayed it down with a jet nozzle on my garden hose to get some of the dirt off too. Finally I blasted it with compressed air and changed the blades out. It was probably raised up like that for about an hour. After lowering the front end back down the mower refused to start.

It turns over no problem but no ignition. I changed the gas out for fresh gas. I checked the fuel filter and fuel bowl. I tried spraying brake cleaner in through the air vent and then sparkplug hole but no sound of combustion. Cleaned out the carburetor which was in good shape anyway. Replaced the spark plug which didn't look too bad. Checked my wiring connections to be sure power was getting to the plug, it is. Drained and changed the oil.. None of this resulted in the lawn mower firing up. It just cranks round and round as if gas wasn't flowing but it is.

Any help on this will be appreciated.


#2

B

Born2Mow

  1. The first place to look is always at the just completed work.
  2. Your first level of diagnosis is always these 3 things: Fire, Compression, and Fuel.
  3. The second level is the timing of those first 3 items.
You wrote quite a bit (thank you), but missed all the needed details.
Example: You replaced the plug, but you didn't tell us if the plug was sparking when the engine was turned over.
Example: You replaced the fuel, but was fuel getting to the combustion chamber ?

But getting back to item number 1, I'd want to know where all that garden hose got pointed. Did the carb, fuel tank, and/or air filter get hit with the garden hose ?? 4 or 5 droplets of water in the carb is all it takes to keep the engine from receiving fuel through the carb. If starting fluid inside the air intake allows it to hit 3 or 4 times, then you may have simple water intrusion.


#3

JamesD

JamesD

Thank you for the reply.

The water from the hose was directed at the underside of the mower deck and through the air vents over the blades only. I don't think much water could have reached the engine, carb, or gas tank granted it was a jet stream and the water did ricochet in many directions.

At the time I was rinsing the deck nothing was disassembled and so I don't belive any water could have entered the fuel tank or the carburetor. None hit the air filter for sure. It was dry.

As for the spark plug.. I did crank the engine with it out and attempted to see the spark. I could not but thought it might just be too bright out so I touched it and felt the electricity. There was power. Maybe there was no spark though. It was wet but I am not sure if it was wet with gas or oil? I cleaned it with brake clean and reinstalled it.

When I cleaned the carburetor I was pretty sure there was no clogs but I might take another look at the float and needle as I did not disassemble those parts last time. However I did see gas misting out of the open air vent so I'm pretty sure gas flow is not a problem.


#4

JamesD

JamesD

I used the brake clean in place of starter fluid through the air intake. No ignition at all.


#5

B

Born2Mow

The plug will be wet with fuel after a short "attempt to crank" session, if the carb is acting correctly.

When the plug is out and laid on the cyl head, you should be able to see a bright blue spark day or night.


#6

B

Born2Mow

JamesD said:
I used the break clean in place of starter fluid through the air intake. No ignition at all.
Click to expand...
If you KNOW that spray can be used as "starter fluid", then OK. I have no such experience.

Confirm your suspicions with the plug out and laying on the cyl head.


#7

JamesD

JamesD

I just rechecked the spark plug the way you suggested and got no spark. I touched the tip and felt nothing either. So somehow I lost power to the plug.


#8

B

Born2Mow

Then trace why your ignition suddenly quit. Water in the kill button ?? Throttle in the wrong position ?? Broken wire ?? Ignitions don't suddenly quit. There's an 85% chance it's something you did while cleaning.

I'm not scolding you... that's just the way it is, brother.


#9

JamesD

JamesD

No I get it. That's why I'm here. Had you not advised I might not have looked at the plug again but now I've got something to go on. I'll trace the wires and look for failures.

Thanks man! Heading to work but I'll post back what I find.


#10

B

bertsmobile1

Firstly lifting the mower like that should not have caused you any grief.
That is the way I service all mowers and I lift them up with a yard crane.

Take the blower housing off then remove the kill wires on the coils and try again
If you get a spark then one of the safety switches is acting up or the kill wire ( ground wire ) is shorting to ground .
If you get no spark with the kill wires removed then the coil is deceased and that will just be a coincidence .


#11

JamesD

JamesD

Glad to hear lifting the mower was likely not the problem! I was worried I might have leaked oil somewhere I shouldn't have.

I'll check the ignition coil next chance I get.

Thank you.


#12

B

bertsmobile1

Only thing to watch when lifting up high is the battery leaking acid & the tank leaking fuel through the cap
You remove the former and put some cling wrap over the tank filler then screw the cap on


#13

JamesD

JamesD

Well, I though I had the problem figured but not so fast. I checked the magneto and spark plug cable. I found that the wires at the spark plug end of the cable were frayed a bit from some past damage before I owned this mower.
The boot was torn and had electrical tape around it. I removed the boot and the metal connector that the plug sits in. I cut back the insulation to expose good wire, attached a new connector, crimped it and replaced the boot (which is in two pieces broken in the middle).
I can confirm that the magneto is working, power is again getting to the metal connector at the spark plug end of the cable, but still no spark from the plug when touching the engine block.
I removed the plug from the cable, held the metal connector near the engine block and cranked the engine. While doing so I was able to get electricity to arc from the metal connector to the engine.. But it seems to not want to pass through the spark plug new one or the old.
Befuddled.


#14

JamesD

JamesD

My best guess at this point is the wiring from the magneto is at fault. Going to replace the magneto and cross my fingers.


#15

S

slomo

Hope you were grounding the spark plug electrode to the engine block. You get spark but not with any spark plug attached. So were the plugs dropped on the ground?

slomo


#16

JamesD

JamesD

Problem solved. Plugs were good, the magneto was making power but perhaps not enough. Otherwise it was the actual cable. But seeing as the cable is non removable I got the new magneto and slapped it on. The spark is back! Unfortunately, I have blown the breather gasket and leaked oil haha. Oh well. That's an easy fix and I'll be up and mowing again. Thank you all for your help.


#17

D

DELTASCIENCES

JamesD said:
The mower is a 42 inch poulan pro automatic with a briggs and stratton 17hp intek motor.
Mower PN: pr17h42sta

Mower was running fine last time I cut the grass.

After sitting about a week, I found that grass had built up under the mower deck so rather than removing the deck to clean it I just lifted the front end of the mower until the wheels were about shoulder height. I braced it there with a board and scraped the deck to remove the large chunks of grass. I then spayed it down with a jet nozzle on my garden hose to get some of the dirt off too. Finally I blasted it with compressed air and changed the blades out. It was probably raised up like that for about an hour. After lowering the front end back down the mower refused to start.

It turns over no problem but no ignition. I changed the gas out for fresh gas. I checked the fuel filter and fuel bowl. I tried spraying brake cleaner in through the air vent and then sparkplug hole but no sound of combustion. Cleaned out the carburetor which was in good shape anyway. Replaced the spark plug which didn't look too bad. Checked my wiring connections to be sure power was getting to the plug, it is. Drained and changed the oil.. None of this resulted in the lawn mower firing up. It just cranks round and round as if gas wasn't flowing but it is.

Any help on this will be appreciated.
Click to expand...


#18

D

DELTASCIENCES

if spray carb cleaner in intake and there is fire nd nothing happens it can only be compression those inteks are bad about sticking valves order a valve cover gasket set take covers off. its a easy fix.


#19

JamesD

JamesD

Thank you. My compression is good though. I've adjusted the valves with the appropriate shims to help the mower run smooth. When I sprayed the brake clean (which is flammable) into the air intake I was not getting any combustion because I had no spark.


#20

D

DELTASCIENCES

I DONT EVER CONDONE disableing safty switch but you have a loose wire or corroded connection pull ground wire on motor you should get spark then track done connection or switch probably loose or corroded


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