20hp briggs & stratton surging

[ILENGINE]

ILengine has some GOOD info in his post @2. Did you try that?
Sometimes on those Briggs with the Nikki you can back off little bit CCW on the CW rotation of the governor shaft when doing the static gov adjust for full throttle on the carb and get less governor control hunting. When I say little bit it's only about 1/16 of an inch difference and mostly a adjust and try because the governor shaft only rotates 1/4 turn or less full travel for the static adjust.

Very true when setting the static governor adjustment you don't want to put tension on the governor shaft when making the adjustment. Just need to rotate shaft to stop and then tighten the arm. If tension is put on the shaft when adjusted will create a governor sensitivity surge.

 

[oldntired55]

After I posted this I see now that you just posted the engine info.
Below is some hints. You WILL FIND the answers to your questions about proper adjusting in the governor section of the Briggs twin Intek OHV service manual. But you need to do the test ILengine suggests in post #2 first. If you have a air leak at the manifold it will have your issue and no adjustments will correct. source of air leak is the o-ring at the intake manifold.
Appears MAYBE from your hints you have a dual throat Nikki MAYBE on a twin engine?
Model type and code would help us?????????????
Most likely not the governor inside the engine.
Have you ever seen the engine operate normal or is this a new to you engine?
Yes Bubba could have messed with the springs???

If that is a Briggs twin each time you change to another NIKKI carb you will HAVE TO go through the steps in the service manual for STATIC governor adjust then low idle the governor idle (which is bend adjustment for the gov idle spring) and then HIGH rpm limit (which is a bend adjustment) You will have to go through these steps if the donor NIKKI carb governor and throttle control is not correct when tested. (look in the correct service manual for the correct steps for such.

ILengine has some GOOD info in his post @2. Did you try that?
Sometimes on those Briggs with the Nikki you can back off little bit CCW on the CW rotation of the governor shaft when doing the static gov adjust for full throttle on the carb and get less governor control hunting. When I say little bit it's only about 1/16 of an inch difference and mostly a adjust and try because the governor shaft only rotates 1/4 turn or less full travel for the static adjust.

this is a 20hp v twin intek donor engine from a junk tractor with the 2bbl Nikki with the black plastic fuel transfer tube and 1 main jet., it has been sitting for 4 or 5 years. i will check the governor settings again, both idle and high speed. and try to cheat the governor back a bit. it has the aluminum intake, so no o rings to leak. i will have to try some new intake gaskets. also will try squirting some wd40 around and check for air leaks, as i found many a leaking intake back in the garage days.

 

[oldntired55]

Very true when setting the static governor adjustment you don't want to put tension on the governor shaft when making the adjustment. Just need to rotate shaft to stop and then tighten the arm. If tension is put on the shaft when adjusted will create a governor sensitivity surge.

i will recheck governor adjustments...and post back a reply. thanks

 

[oldntired55]

OK, so now i am removing this engine i just installed. i wanted to warm it up BEFORE re- adjusting the governor.. it went FULL throttle, i was afraid the rods would fly out before i could shut it down..i guess maybe the governor came apart, maybe it was failing last week? who knows..a teardown will tell the story. i will repost after teardown. thanks for all the help so far..

 

[oldntired55]

Update... i believe i found my errant governor hunting problem...parts are ordered... cant wait to get it together.

 

[oldntired55]

Update... i believe i found my errant governor hunting problem...parts are ordered... cant wait to get it together.

i really think one weight was off when i started it the first time...

 

[Forest#2]

You have been lucky so far that small piece of the bad governor has not caused any major damage. It will eventually happen if you do not retrieve all.

BE SURE you retrieve ALL the small pieces from inside. I have a large metal lid/pan from the top of a 55 gallon barrel that has a lip and I take the block outside shop and put screen wire over the lid and flush the block with diesel using a hand sprayer and roll and tip the block and use magnets to search for exploded pieces. Use the replacement governor to compare to your exploded puzzle pieces to get an idea if you have retrieved all. If you don't get all the pieces the engine gears will eventually find them.

Also make sure the governor is orientated properly when re-installing the sump.

Hint: When first starting up that type governor engine I've been deep into I purposely set the static governor opposite of normal so as when the engine is first started so as the governor SHOULD hold the engine at idle instead of high rpms. Set throttle control at idle also or manually tie the carb to idle position. You know then when you let it have governor control it should immediately stay at low rpms and you are ready to do the ignition off immediately. After you see the governor holding the engine at idle or low rpms and letting the engine warm up at low rpms then set the governor static adjust normally by the book for the high rpms governor control know the engine should immediately start and operate correctly with governor control.
Max over speeding rpm's governor at cold startup is not a good thing even when you are trying to kill the engine.

 

[oldntired55]

You have been lucky so far that small piece of the bad governor has not caused any major damage. It will eventually happen if you do not retrieve all.

BE SURE you retrieve ALL the small pieces from inside. I have a large metal lid/pan from the top of a 55 gallon barrel that has a lip and I take the block outside shop and put screen wire over the lid and flush the block with diesel using a hand sprayer and roll and tip the block and use magnets to search for exploded pieces. Use the replacement governor to compare to your exploded puzzle pieces to get an idea if you have retrieved all. If you don't get all the pieces the engine gears will eventually find them.

Also make sure the governor is orientated properly when re-installing the sump.

Hint: When first starting up that type governor engine I've been deep into I purposely set the static governor opposite of normal so as when the engine is first started so as the governor SHOULD hold the engine at idle instead of high rpms. Set throttle control at idle also or manually tie the carb to idle position. You know then when you let it have governor control it should immediately stay at low rpms and you are ready to do the ignition off immediately. After you see the governor holding the engine at idle or low rpms and letting the engine warm up at low rpms then set the governor static adjust normally by the book for the high rpms governor control know the engine should immediately start and operate correctly with governor control.
Max over speeding rpm's governor at cold startup is not a good thing even when you are trying to kill the engine.

that was my initial thought, when i get this back together thursday, to limit the throttle at the carb... ill keep you posted, thanks for the info

 

[oldntired55]

Ok this story seems to get nothing but WORSE... now, upon inspection of the gov gear shaft, i see there is no snap ring that goes into the case. also, i notice some galling right above the lower snap ring groove... my question is, is there a part number for a new shaft with both snap rings? the ring is NOT inside the case, i looked and looked with a magnifier.the only thing i can say for certain, is the gear was 'snapped in' the case, as i had to gently pry it out. i have looked and looked, but i cant find the lower ring... the only thing i can think, is that i rinsed it out of the crankcase when i washed it out. any source for a new Briggs shaft?

 

[Freddie21]

Do we know that we have good, unobstructed, fuel flow to the carb?