Engine craftsman twin cylinder.

rowdy45176

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I have a model 917271920 wi th motor model # 407777 0167 E1 that is only running on one cylinder. I can disconnect the spark plug wire on one cylinder and it still runs, reconnect the other one and disconnect the side that it ran on and won't start. Tried starting fluid no results. Checked the ohms on the coil and both the same, am getting spark (weak) on dead cylinder but won't run on it. Any ideas??
 

ILENGINE

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Remove the blower housing and disconnect the small wire that hooks to the module on the one that you think is bad and check spark. if still weak or non existant replace module. if you now have good spark, check the wire for bare or grounded spots. Some of the briggs engines have diodes in the kill wire and could be a bad diode.
 

rowdy45176

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Remove the blower housing and disconnect the small wire that hooks to the module on the one that you think is bad and check spark. if still weak or non existant replace module. if you now have good spark, check the wire for bare or grounded spots. Some of the briggs engines have diodes in the kill wire and could be a bad diode.

I have removed the wire from both coils and it still runs on the one cylinder only. The dead cylinder is not loaded up with gas. Tried getting an ohms reading and from the coil to the motor housing I have resistance.
 

motoman

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rowdy, my intek pushed a guide which destroyed the cam. Engine could not lift valve. Only ran one cyl. Compression same iin both. Remove valve covers and inspect guide positions.
 

rowdy45176

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rowdy, my intek pushed a guide which destroyed the cam. Engine could not lift valve. Only ran one cyl. Compression same iin both. Remove valve covers and inspect guide positions.

thanks will try that it has compression but like I said even with starting fluid in the spark plug hole won't fire so your idea make sense
 

rowdy45176

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It has a broken push rod and a bent push rod, what could be the possibly causes other than timing?? Is it worth even fooling with. It is the 20,5 twin cylinder
 

motoman

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It has a broken push rod and a bent push rod, what could be the possibly causes other than timing?? Is it worth even fooling with. It is the 20,5 twin cylinder

There are pros who can also answer this. The bent pushrod can be from a valve sticking in the valve guide in the closed position so that the cam lobe meets an "immovable" object. Once that contest is over the pushrod is not long enough to stay engaged in the rocker dimple (.080" on my Intek 24). It can then drop out or continue to be hammered. My experience is only on my Intek, but I have read that drop out is fairly common and often you can simply replace the push rod and adjust the valve (s) Sticking is believed to be from heavy deposits in the guide (usually the exhaust valve), and is related to overheat and neglected oil. It can be aggravated by immediate shut down of overheated head.

A broken pushrod : my experience is the Intek ingested (yes, it was inside the pan) the unit, it passed through the timing gear. When I heard this I stopped immediately. A picture of the chewed/broken pushrod is in this forum. In my case I had reinstalled a head which had pushed a guide. How the pushrod launched through the oil return hole is beyond me. You have not told us how old your motor is , or if you can work on the motor.
 
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DaveTN

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There are pros who can also answer this. The bent pushrod can be from a valve sticking in the valve guide in the closed position so that the cam lobe meets an "immovable" object. Once that contest is over the pushrod is not long enough to stay engaged in the rocker dimple (.080" on my Intek 24). It can then drop out or continue to be hammered. My experience is only on my Intek, but I have read that drop out is fairly common and often you can simple replace the push rod and adjust the valve (s) Sticking is believed to be from heavy deposits in the guide (usually the exhaust valve), and is related to overheat and neglected oil. It can be aggravated by immediate shut down of overheated head.

A broken pushrod : my experience is the Intek ingested (yes, it was inside the pan) the unit, it passed through the timing gear. When I heard this I stopped immediately. A picture of the chewed/broken pushrod is in this forum. In my case I had reinstalled a head which had pushed a guide. How the pushrod launched through the oil return hole is beyond me. You have not told us how old your motor is , or if you can work on the motor.

Wow! Ate it up and passed it on through...that is something! How did the "Re-Installed Head" push the guide? Just wondering what caused it to eat the push rod? If you stay in this business long enough, you'll see or hear it all. Thanks for the story.
 

motoman

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Dave, actually passed it through and then ate it. The original head pushed the guide..It took a long time to believe what I had found (no valve lift, no cam lobe). Then , the stubborn type, I disassembled the pushed guide . You cannot buy replacement guides ( hint, hint BS knows). So I measured everything (e.g., od of guide, id of guide hole), and reassembled. The engine ran ok until the pushrod went into the pan. This , I believe, was not related to the pushed guide, maybe poor valve adjustment? By then BS had sent me a new head fully assembled. After the second tear down and reassembly I have not had a problem, but I did put an oil cooler on the tractor. Also a head temp probe. I will post the head temp soon during worst conditions:85F, 3 bagger full of grass, on grade. I believe the head overheated and softened the aluminum, loosening the head grip on the guide.

Old timers are tired of my theory. Perhaps Briggs received a bunch of bad heads (alloy, heat treat). The pros are afraid to speak , especially those with ties to BS, and I understand. There have been responses from them that my experience is not so unusual. If you guys are handy or used to working car engines , the tractor engines are cake, no hoists ,etc.:tractor:
 
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