Briggs Vtwin giving me a fit

[RED-Z06 2,491]

Timing was dead on no slippage, but an interesting development on compression..although not uncommon, 130psi on rue right side which is normal, 180psi on the left, which is also normal if the compression release has a problem...these lobes are splined to the cam, its conceivable that the splines have distorted..i guess, odd that they were even previously but its definitely higher on one side now.

 

Guess ill order a cam and lifter kit...and pull the engine off

[Snoopy11 5,717]

@RED-Z06... have you actually physically verified that both cylinders are firing? Most of the time when Briggs engines bog under load... it is 1 of 2 things... no spark on 1 side... or... see below...

 

On these some series Briggs twin, it is also possible for the exhaust pushrod (particularly on the "driver's" side) to physically fall down into the crankcase... so I would pull valve covers and re-verify.

 

One thing I can say... that engine has EVERY symptom of only running on 1 cylinder... bogging under load... choppily pulling the dead cylinder along... running normally without a noticeable issue at idle...

 

Don

 

 

[RED-Z06 2,491]

12 hours ago, Snoopy11 said:

@RED-Z06... have you actually physically verified that both cylinders are firing? Most of the time when Briggs engines bog under load... it is 1 of 2 things... no spark on 1 side... or... see below...

 

On these some series Briggs twin, it is also possible for the exhaust pushrod (particularly on the "driver's" side) to physically fall down into the crankcase... so I would pull valve covers and re-verify.

 

One thing I can say... that engine has EVERY symptom of only running on 1 cylinder... bogging under load... choppily pulling the dead cylinder along... running normally without a noticeable issue at idle...

 

Don

 

 

Runs smoothly on both cylinders with the opposite cylinder isolated out, neither feels weak, and both can run the deck on their own without stalling.  All 4 push rods are intact, rockers lashed, and rechecked peak lift again and its even.  It does sound like it drops a cylinder momentarily, under heavy load, but...compression, spark, fuel...all seem fine, leakdown was great.  The only concern i have is the plugs coming out clean...no deposits, white ceramic and bare clean ground strap...indicates lean but, no surging..no popping out the intake, which these were notorious for when leaned out.

[Snoopy11 5,717]

@RED-Z06... have you pulled heads to ensure valves are seating...?

 

Also sounds like potential leaky valve seats... per one of my engine friend gurus...

 

Don

 

 

[kpinnc 13,936]

Not sure if this is an Intek or Vanguard- but the Vanguards have a known issue with the main sump gasket developing a minor leak. Shows up primarily while running, and allows pulse pressure issues. If you're using a crankcase pulse fuel pump, you get either too much fuel, or not enough. Can be very frustrating because it mimicks carburetor problems that aren't there. There is an upgraded gasket kit that supposedly corrects the problem. Of course that requires almost a complete engine teardown.

 

Mine developed just enough over pressure to overwhelm the carb float shutoff. Ran great until you turn or lean the tractor, then sputter spit and die. 

 

You might try a 1-2 psi electric pump in place of the pulse pump and see if anything changes. 

Edited July 31, 2022 by kpinnc

[RED-Z06 2,491]

11 minutes ago, kpinnc said:

Not sure if this is an Intek or Vanguard- but the Vanguards have a known issue with the main sump gasket developing a minor leak. Shows up primarily while running, and allows pulse pressure issues. If you're using a crankcase pulse fuel pump, you get either too much fuel, or not enough. Can be very frustrating because it mimicks carburetor problems that aren't there. There is an upgraded gasket kit that supposedly corrects the problem. Of course that requires almost a complete engine teardown.

 

Mine developed just enough over pressure to overwhelm the carb float shutoff. Ran great until you turn or lean the tractor, then sputter spit and die. 

 

You might try a 1-2 psi electric pump in place of the pulse pump and see if anything changes. 

Im working on finding another engine, its an intek, early version.  I have to measure the crank, i found a 22hp on a Husqvarna rider for free if it fits

[Bill D 2,130]

29 minutes ago, RED-Z06 said:

Im working on finding another engine, its an intek, early version.  I have to measure the crank, i found a 22hp on a Husqvarna rider for free if it fits

Upgrade to a Vanguard or Kawasaki if you can find one.   If you can find a free engine, make it fit.  Plenty of ways to make it work.

[RED-Z06 2,491]

27 minutes ago, Bill D said:

Upgrade to a Vanguard or Kawasaki if you can find one.   If you can find a free engine, make it fit.  Plenty of ways to make it work.

The issue with swaps is always exhaust for me.  I do like the vanguards though.  If my Cub ZForce ever lays Down im definitely pulling the 23hp Command...its buttery smooth 

[Bill D 2,130]

 

On 7/31/2022 at 2:34 PM, RED-Z06 said:

Im working on finding another engine, its an intek, early version.  I have to measure the crank, i found a 22hp on a Husqvarna rider for free if it fits

Any more progress on this?  I know the Intek singles are known for blowing head gaskets.  Any chance you have a head gasket that has failed, or is starting to.  If your doing an engine swap, please post pictures.  Bill

[RED-Z06 2,491]

6 minutes ago, Bill D said:

 

Any more progress on this?  I know the Intek singles are known for blowing head gaskets.  Any chance you have a head gasket that has failed, or is starting to.  If your doing an engine swap, please post pictures.  Bill

Looking for an engine, a new one is about $900, if it was an exmark or toro id bite the bullet but its a yazoo and parts are non-existent so its never smart to dump money into them.  Had a line on a nice rider with a 22hp engine and bad trans, but the guy never got back with me on selling it.

[Bill D 2,130]

On 8/4/2022 at 1:38 PM, RED-Z06 said:

Looking for an engine, a new one is about $900, if it was an exmark or toro id bite the bullet but its a yazoo and parts are non-existent so its never smart to dump money into them.  Had a line on a nice rider with a 22hp engine and bad trans, but the guy never got back with me on selling it.

Trying pulling the heads and change the head gaskets.  The Intek singles are notorious for blowing head gaskets.  Gaskets are cheap enough to risk the money.  I've seen the singles run with blown head gaskets, just not well and without much power, and the engine had decent compression numbers even with the failing head gasket.

Edited August 6, 2022 by Bill D

[RED-Z06 2,491]

On 8/4/2022 at 10:25 PM, Bill D said:

Trying pulling the heads and change the head gaskets.  The Intek singles are notorious for blowing head gaskets.  Gaskets are cheap enough to risk the money.  I've seen the singles run with blown head gaskets, just not well and without much power, and the engine had decent compression numbers even with the failing head gasket.

It passed a leakdown test on both sides, but yes the singles were notorious for it, and briggs refused to add a fire-ring to the new engines and the replacement gaskets

[Bill D 2,130]

8 hours ago, RED-Z06 said:

It passed a leakdown test on both sides, but yes the singles were notorious for it, and briggs refused to add a fire-ring to the new engines and the replacement gaskets

I found a company online that makes copper gaskets for the singles.  Maybe they have gaskets for the twins.

Edited August 11, 2022 by Bill D