Runaway engine on Briggs & Stratton 407777 0167-E1?

I had the same problem on the same model. This problem seems fairly common for this model engine. I had to take the engine apart to find that the governor gear had blown apart inside the engine. Luckily, the engine was not damaged by the shrapnel. To repair this problem I had to:

A) Remove the mower deck
B) Disconnect the battery
C) Drain the oil and gas from the engine and tank
D) Disconnect all electrical connections between the mower and the engine
E) Remove throttle and choke assembly
F) Unbolt the engine from the chassis (4 bolts)
G) Remove the V-Belt (Drive belt)
H) Remove the Engine Pulley
I) Remove the engine from the chassis
J) Remove the head cylinder No. 1 (10 bolts)
K) Remove the Governor Gear and all shrapnel from the engine
L) Replace the governor gear assembly
M) Replace the Crankcase gasket
N) Replace the Oil seal (PTO side)
O) Remove the oil pump shaft
P) Reattach the head cylinder No. 1 (Lubricate gasket)
Q) Re-install the oil pump shaft

- You get the idea; from here put everything back where it goes. A tip to remember is never force the head cylinder into place, and replace the locktite on the bolts for the head cylinder. This involves exposing the crankshaft and you don't want any dirt or debris in this chamber. If I missed any steps I apologize; I don't know everyone's familiarity with engines. My advice is if you are not comfortable with the inside of an engine, a repair shop may be a good option. The repair cost would probably be around $200. The parts according to B&S come to about $21.10.

Parts required (Original Briggs & Stratton Part Numbers) :
Craftsmen Tractor - Model 917.272441
B&S Engine - Model 407777, Type Number 0121-E3

394348 - Gear-Governor
690945 - Gasket-Crankcase
690947 - Seal-Oil (PTO Side)

It is strongly recommended to replace the gasket, though if you are careful you can save the existing gasket. The Oil Seal (PTO Side) is for good measure. The Governor Gear is the actual broken assembly.

Brandon Brooks
September 2008

I removed the lower end. What I found that the govenor gear had snapped off the shaft. I think the side pressure in the shaft wore the case causing it to gauled and the shaft to lock then it was twisted off at the level of the case. I will be checking with the local repair shop to see if there is a fix for this since the case will have to be modified to fix it.

Homer
June 2008

Having the same problem with the same model. I'll see what I can find.

Homer
June 2008

Jerry,

I was wondering if you ever found anything definitive on this problem. As of today (5/18/08) , I am having the same problem on the same model engine. It appears that the throttle is not even coming off the stop. I am wondering if the butterfly valve may have broken off or something. I am going to look into it further in the next day or two. If I find anything, I'll let you know.

Stace

Stacey Weston
May 2008

Jerry,

I was wondering if you ever found anything definitive on this problem. As of today (5/18/08) , I am having the same problem on the same model engine. It appears that the throttle is not even coming off the stop. I am wondering if the butterfly valve may have broken off or something. I am going to look into it further in the next day or two. If I find anything, I'll let you know.

Stace

Stacey Weston
May 2008

LOOK DOWN THE INTAKE OF THE CARB TO SEE IF ANY THING ISINTERFERING WITH THE THROTTLE U MAY NEED TO TAKE OF THE FILTERS

A.RAMSAY
May 2008

It sounds like the link from the govenor arm (on the engine) to the carb throttle link has somehow become disconnected. There will therefore be no govenor control. You MUST sort this before using the mower, or you will be able to measure the engine life in SECONDS.

phil_saunders@bigfoot.com

Phil Saunders
May 2008