12 replies to this topic

[TGetz]

MODEL NUMBER 917.275702 BRIGGS ENGINE-MODEL NUMBER 445677, TYPE NUMBER 0413-E1 

 

24HP Briggs and Stratton V-Twin Engine.

 

I need help finding the issue, so that way I don't put more money than what I need into this engine. It backfires through exhaust, not intake. I tore the entire engine apart, because from what I read I had believed it to be a cam shaft worn. Cam looked great, everything inside the case looked great, put it back together with a whole new gasket kit, cleaned up the heads, the valve seats look good, the valves aren't bent, the push rods are straight, valve lash is great, no troubles there. It has spark on both cylinders, but if you pull #2 wire off while running, she shuts off, pull #1 it stays running and no changes. #1 plug is always wet, with fuel. I took the carb apart, and cleaned it and put new gaskets in, what I did notice was the one "jet" was bigger than the other, so I put the smaller looking jet in the side that had the bigger looking jet to see it someone rebuilt this carb and messed up. Still the same thing going on. I've never removed the flywheel because I don't have the right tools to pull that off, but the key looks to be where it should be and not sheared off.

 

Got fuel, got spark, but #1 plug is always wet, and backfires. I don't know what else it could be from what I've done already.

[TGetz]

Compression is 130 in #1, 120 in #2.

[shorty]

Welcome to GTtalk! I don't know much about your engine. It almost sounds like the timing is off a little.

[TGetz]

I have the cam and crank timed correctly, and the flywheel key isn't sheared. I'm really at a loss, I have a dead cylinder that the plug gets wet, with fuel, even though it got spark. I think I might swap coils from one side to the other.

[Eric]

You may have a weak coil,plug, or bad ignition wire. All cheap to replace. But if that doesn't seem to do it I would agree that the timing seems slightly bad. Small engine timing is tricky sometimes. I have had to time the same motor multiple times and finally got it right, never did figure out how that one came to run right!

[TGetz]

Well all the timing marks were lined up perfect, and i turned the engine over a few times just to make sure it lined up at the end before putting the case back on and it did. I swapped coils and #1 is still dead. I keep reading about bad valve seats but you would think I wouldn't of had the good compression reading. The plugs I swapped 3 times. I don't want to put money into this that might not fix it, but I'm going to need the rig for this winter to blow snow. I'd hate to buy a head, and a carb, only needing one of them.

 

But I've read rebuilding carbs don't fix the issue, you have to replace them, and I've heard valve seats are an issue. I also read of someone having the same issue I'm having, and it be a coil, but that was with the older vtwin that had one coil that ran both cylinders.

 

I don't know I'm flustered.

[TGetz]

I believe to have found the problem. I'm not getting the readings that I should be getting with a correctly working diode for the coils.

[TGetz]

Turns out the diodes are doing their job and still having the issue. Don't know what else to do than the replace the head, and carb and hope the problem goes away.

[shorty]

Did you check the wires and strength of spark on the #1 side compared to the other?

[TGetz]

I went as far as swapping the coil and plugs from the working cylinder to the dead cylinder, and still the dead cylinder was dead, even with the working cylinders coil and plug, and the working cylinder worked, with the dead cylinders plug and coil.

 

I just ordered a new carb, and going to try copper plugs. See what happens.

[shorty]

Just throwing a thought out there, you might have checked it already. Is the coil on the dead side getting power?

[craftsmanmowerfreak]

on these vtwin the kill wire running between magnetos (coil) has a diode in it. but not saying its your issue because when that fails its usually no spark at both cylinders swap your magnetos around and try it if issue jumps to other cylinder you know what your issue is.

Edited by craftsmanmowerfreak, October 06, 2015 - 08:32 AM.

[EricFromPa]

Did you try Unplugging the kill wire from Both coils and start it?

 

I had problems with diodes on an older Vertical 16 V-Twin vanguard.It had 2 diodes 1 going to each coil.I unplugged both of them and it ran good,plugged them back in and lost fire on the left cylinder.

 

 

What did you set your valve lash to?

Edited by EricFromPa, October 09, 2015 - 01:14 AM.