Briggs 33R877-0034-G1

[KE4AVB]

Boy this one is a royal pain.

History.

Several Techs has had their hands in this one.

Root problem was caused by the ACR failing jamming pieces into the gear train shattering the starter Bendix.

Replace Bendix and camshaft. Was running fine when it left but fail upon the customer unloading it.

It now surges heavily if load is applied and doesn't stop until engine shutdown. Now if you start it at idle and ease up the throttle you can get to high idle without the surging but as soon you try engaging the deck it back to surging.

I done gone back in and checked the camshaft, crankshaft gear, and key.

This is same engine that they left the stator wire retaining clip under the flywheel which destroyed the stator.

I now going to try a new carb but I am running out of ideas of what to look for. Never seen one doing this so it is a new one on me.

[bgsengine]

could there maybe be a hairline crack in the intake port? just wondering because of the ACR/valve/camshaft damage along with possibly multiple R&R of the head (poor torque technique, dropped head on floor, etc)

[bluemower]

I don't recall your previous mention of this engine. here are more ideas:
1. in the event of a slightly lean mixture, what happens when you slightly close the choke?
2. any chance the exhaust valve has a slight leak?
3. what happens when you manually hold the governor linkage from moving.
4. since there was some shrapnel floating around during the failure, any chance the oil slinger/governor mechanism may have some damage - perhaps causing the governor to have a binding point?

[Arkie]

I've felt your pain on them Briggs Single cyl Intek's and also the Briggs twins. Lots of wasted labor hours involved sometimes. Lots of patience and thinking of throwing in the towel and going for a crying rag. Next thing to whipping on a dead horse.

I keep a GOOD Walbro LMT carb laid back to sub in place of those Nikki's.
After I get a good run with the Walbro I can usually eventually make a Nikki come around.

I use gasket material and make intake gaskets so as I do not have to trust the intake o rings for a good seal. (On both the singles and the twins) I also suspect surging adds to failures of the wimpy camshaft compression release. I also flinch if I see the single cyl Intek engine kick backwards when key is turn off as the engine dies)
Remove the intake manifold at the head and install a good gasket and see if someone installed a restrictor plate, If no restrictor plate might consider trying one.

Really lots more ?'s and unknowns when others have already been trying things. Had a twin with somewhat same symptoms awhile back and it had wrong governor spring.

Not user friendly trying to manually add some choke to those single cyl inteks due to the throttle/choke arrangement so as to check for lean condition. (another Briggs engineers weak upstairs idea)

How does it act if you hold the governor arm from moving?
(if idles rough or still surges by holding the governor arm steady is a hint of a carb/air issues usually)

[KE4AVB]

Well I finally get to close this one out. I never had one to do this.

After all the parts swaps in attempt to find the problem. I even tore the engine down a third to verify that the governor was definitely good and that the camshaft lobes were in the correct positions.

I finally replaced the new Autolite spark plug that one of the other techs put in the engine. It was the only thing I hadn't tried changing. It apparently was what was causing all the heavy surging off idle. It is definitely one to remember for a very long time. Apparently it was failing under the higher compression loads.

[Arkie]

I've had a bad spark plug make me feel really weak upstairs couple of times.

Changing the spark plug is one of the first things I do anymore due to them making me feel really lame brained unless it's something that is quite obvious.

Most generally the ones I change the fastest has the name CHAMPION attached.

I seen your post in the other forum about this engine and you are getting lots of good answers but none correct as of yet.

[KE4AVB]

Yes there times you can feel dumb. In those cases you just have to try everything based on experience. This one had me had at a lost what was causing the problem. Never had a plug to cause this problem but had to be the only thing I had not tried.

Now of I had one these engines sneezing last year and it was an intake gasket problem.

My biggest trouble plug here is the NGK CMR6 and 7 plugs which I replace with a Bosch plug. Those I have seen from being dead to making a couple strange problems. One engine sounds like it had a rod knocking and the other was dieseling. The one with the rod knocking the customer got mad when I told it was the spark plug causing the knocking and still insisted it was the rod. Once he found what I would charge to replace the rod he shut up.

[38racing]

I've got a briggs vtwin . Runs fine except for an irregular miss at full rpm. Disappears is I slw it a bit. Thought maybe choke was closing at full throttle position but althoug I can't see choke plate I'm pretty sure it's wide based on lever position and I did back off cable a bit . I just verified valve clearances are good. I notice it has champion plugs when I serviced it I never replaced the plugs. I use ngk but am down to my last one. I put it in side where I think I hear the miss (actually like a muffler bag). Haven't fired it up yet, waiting for rtv to cure.

[Arkie]

38racing:

You lost me with this statement????

I put it in side where I think I hear the miss (actually like a muffler bag). Haven't fired it up yet, waiting for rtv to cure.

[38racing]

38racing:

You lost me with this statement????

I put it in side where I think I hear the miss (actually like a muffler bag). Haven't fired it up yet, waiting for rtv to cure.

Lol. I need to proof read. I put the only new plug I had available in the cylinder which I thought the miss ( like explosion of unburnt fuel) was occurring. Waiting for rtv from valve cover replacement to cure.