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I have a briggs 17.5 h.p and was told on here to adjust the valves.i did that and still it will not turn over.weak starter?

When you say won't turn over are you saying with starter, but it will turn over by hand? When you sat weak starter did you check for a voltage drop to the starter? If you have a voltage drop find the cause of that before replacing the starter. cables, switches, bad wires ?? weak starter, bad motor bushings?

I don't have an ignition so I jumped from the starter.it will turn over without the plug but once you put the plug in and has compression it will barely move.i can turn the flywheel screen by hand and of course it gets harder on the comp stroke but I can still turn it.brought it to a shop but they tested it but it wasn't tested under a load.wondering if advance auto can test it?i live in the country and we have one shop so I need to try to fix it myself

dwint said:

I don't have an ignition so I jumped from the starter.it will turn over without the plug but once you put the plug in and has compression it will barely move.i can turn the flywheel screen by hand and of course it gets harder on the comp stroke but I can still turn it.brought it to a shop but they tested it but it wasn't tested under a load.wondering if advance auto can test it?i live in the country and we have one shop so I need to try to fix it myself

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when I was jumping it off my car the rpms dropped a lot and the jumper cables got hot

I had same issue with twin 22hp briggs. Adjusted valves to specs and still had problem. Matter of fact tried to turn by had and then engine would backfire and not start. Pulled flywheel and sure enough i sheared key by turning by hand. Went back and tested valve clearence and tightened clearence just a bit and that was the trick. Engine starts very easy and runs much better. Maybe the push rods or valves change a bit after many hours of use so specs may need tweaked.

Start simple, make certain the blades are not engaged or anything else isn't pulling on the engine, check that flywheel key, make sure the valves are adjusted to the proper clearance and make sure whatever wiring you are using to crank it is capable of the amperage load a starter will put on it. I'm assuming nothing is making contact in the engine, such as sparkplugs being too long and contacting the engine or valves being too tight and bottoming out as they open. If the key is good, you have the correct sparkplugs and you're certain the jumper cables are in good condition, then I'm thinking either the valves are still not in spec, the decompression mechanism is not working or you do have a weak starter.

the jumper cables are in poor condition but I have the right plug and adjusted the valves.so lets just say the previous owner hit something hard with the blades ingauaged.could it damage the key enough so the motor spins without the plug?throwing the timing off so I cant get the correct valve adjustment?i didn't think of that,i guess i'll need a gear puller to remove the flywheel

As soon as you remove the nut on top of the flywheel, you'll be able to see if the key is sheared.

ok thanks,ill go out there and look

can someone tell me what size that center nut is and do you loosen to the left or are the threads different direction

dwint said:

can someone tell me what size that center nut is and do you loosen to the left or are the threads different direction

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I don't have a socket that big and have to borrow one

mullins87 said:

As soon as you remove the nut on top of the flywheel, you'll be able to see if the key is sheared.

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do you no what size it is cause the biggest I have is 7/8ths

ok got the nut off and the key is fine.where do I go from here?:confused2:

dwint said:

I don't have an ignition so I jumped from the starter.it will turn over without the plug but once you put the plug in and has compression it will barely move.i can turn the flywheel screen by hand and of course it gets harder on the comp stroke but I can still turn it.brought it to a shop but they tested it but it wasn't tested under a load.wondering if advance auto can test it?i live in the country and we have one shop so I need to try to fix it myself

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I don't understand what you doing when you say jumped from starter? What did the shop test, not under a load? What are you testing at Advance Auto, the battery?
When I pull a flywheel I use a puller, but in a pinch I have pulled flywheels by prying under the fly and hitting the top of the crankshaft with a hammer and punch, but if you do it this way use caution because you can do damage.

reynoldston said:

I don't understand what you doing when you say jumped from starter? What did the shop test, not under a load? What are you testing at Advance Auto, the battery?
When I pull a flywheel I use a puller, but in a pinch I have pulled flywheels by prying under the fly and hitting the top of the crankshaft with a hammer and punch, but if you do it this way use caution because you can do damage.

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He went from the battery to the starter. That is jumping the starter.

Getting the starter tested.

Shop test the starter but not under a load

(( racing is the only sport that you need two balls ))

the mower was givin to me and had no battery or ignition so instead of wasting my money I tried jumping it off my truck.all the safety switches were removed also.when I touched the pos to the starter it barely moved so I took the plug out and it spun freely.the cables were getting hot and my rpms on the truck went way down.i took the starter off and took it to a repair shop but it wasn't under a load.i was wondering if advance auto could check it under a load or volts.this happened to me on my bike.it would jump up and spin but not enough power to turn the motor over.

So just to make sure we're on the same page; the key is fine; the motor spins freely if the plug is removed, and there is no sign of physical damage to the electrode, such as the piston hitting it; the motor will not turn over if the plug is installed. Okay, you don't know for sure the starter is good, but you do know that it bench tests just fine. Do you have another B&S engine that you could rob a starter from? You mentioned earlier you weren't certain the previous owner didn't hit something. Have you verified the crank isn't bent? I would think the flywheel and or PTO pulley would wobble at least a little as the motor spun without the plug in. Getting farther into the motor......if everything else checks out, I have to wonder if the decompression mechanism isn't working. If that is the case, the starter may not be strong enough to spin the motor under full compression.

if its the decompression mech.then the motor isn't worth getting into is it

I would say that depends on how much time do you want to put in it. However, I still think I'd make absolutely certain the starter is strong enough to start it. If it is, then you'll have to drain all the oil, pull the motor out of the mower, flip it over and remove the sump. How much would it cost to fix it? Honestly I don't know as I've never had to fix one. The mechanism isn't very complex and the parts are small, but I've never had to replace any of those parts, or even take one apart for that matter. Since it was given to you, if I were in your shoes I'd pull that bad boy apart just to see what's going on. You have nothing to lose other than time.