# Newbie over-rev problem



## Jeeper XJ (Jul 28, 2010)

New to forum I was wondering if someone would have any suggestions to my over-rev problem?
Its on a 18.5 Briggs Intec It was running fine than it just starting running very fast. You could not throttle it down it just wanted to run. Checked governor springs all are in place, tried to adjust the rod and shaft that goes into lower crank area but could only get it to not run at all or run to a point I was afraid of throwing a rod. Tried to adjust carb. but there is not much to adjust and did not change the way it ran.
Prior to this it used to back fire when you shut it down so you had to throttle it way back to keep it from backfiring.
Anyone have any thoughts? 

Thanks,


----------



## Hoodoo Valley (Nov 14, 2006)

Welcome to the forumJeeper. Way more qualified folks here to give you better advice than I would be able to offer, but what the heck........Have you checked all the lines for leaks? Sounds like it could be something leaking air into the intake.......But that's just me!


----------



## Jeeper XJ (Jul 28, 2010)

Thanks for the welcome. Checking for leaks is a start I'm not used of these type carbs.


----------



## GMAN (Jul 26, 2010)

Jeeper you might check to make sure that the throttle plate in the carb is still there or maybe the screw that holds the plate on the throttle shaft is still there. If it is missing make sure it has not been sucked down the carb. There is an adjustment for the gov. Can you throttle it down at all ? Have you tried manually throttling it down at gov linkage at the sump pan ? I think you can go to B&S website for directions on setting gov.


----------



## Jeeper XJ (Jul 28, 2010)

The cam on the carb that the linkage hooks to is still there. I never though about verifying that the throttle plate was still there!? You can work it by hand and engine still runs the same with no change in RPM or engine sound. I can slow it down by moving/closing the choke plate and cutting back the oxygen but it starts to really run rich and expelling black smoke out the exhaust.
I did try adjusting the governor linkage that goes into the sump pan I slowed it down a bit. When you pull the linkage the engine runs from very fast to scary blow the engine fast. Right now the governor is is sitting at the position to make it run the slowest which is very fast. 
Don't know if related but I did have a loud squealing sound the time I used it before but after I let it cool down and restarted the engine it went away. When it heated up again it started to squeal which I activated the electric blade clutch and it went way, figured it was the electric clutch bearings.

I will pull the carb next to see it the throttle plate is still there. Engine has less than 100 hours on it to have this much problems with it. I questioned the durability of the OHV intek engine when I bought it. Oh well.

Thanks,


----------



## lsmurphy (Sep 12, 2008)

Edit.....

Let us know about the plate, sounds odd.


Scott


----------



## dangeroustoys56 (Jul 26, 2010)

Does sound odd.... another thing to check is the actual governer- it couldve come apart inside the motor.....


----------



## Jeeper XJ (Jul 28, 2010)

Governor seems to be working but that may explain the squealing sound I heard prior to this problem even though the noise went away. I am not familiar with the internal workings of the governor but from the engine schematics it looks like a job pulling the engine and dropping the oil pan/lower section of the engine. Ill try pulling the carb this weekend to see if I can find anything there first. 

Thanks,


----------



## dangeroustoys56 (Jul 26, 2010)

The governer setup is mostly plastic inside the motor- when the motor revs up,the governer is similar to a centrifical clutch - sometimes they just come apart. It should be fairly easy to replace - its right at the bottom of the motor.


----------



## Jeeper XJ (Jul 28, 2010)

Checked the throttle plate in carb and everything is there. I did pull the cover off the engine and noticed the magneto was cocked over to one side with at least an 1//8" gap from the fly wheel magnet. I pulled it and saw where it hit the fly wheel at some point and put a small dent on the edge of the the magneto housing. I smoothed out the dent and reinstalled at .030" from the fly wheel magnet. Engine ran better and slower after re-adjusting the governor but rough. I pulled the spark plug and found it to have a lot of carbon on it. I guess with the magneto was backed off so badly it must have had a really retarded spark resulting in the carbon build up?
So now with a new spark plug and adjusted magneto it is running a bit slower and smoother but it still does not run 100% like it used to. When you throttle it back it doesn't slow down as slow and when it is at cutting speed it sounds like it is too fast until you engage your mower blades. At least it doesn't back fire like it used to when you shut it off unless you had it throttled way down.
I still wonder if the governor weights are messed up on the engine? I may try mowing to see how it does first which I will have to do this week in the 100 degree heat.


----------



## wjjones (May 28, 2010)

Jeeper XJ said:


> Governor seems to be working but that may explain the squealing sound I heard prior to this problem even though the noise went away. I am not familiar with the internal workings of the governor but from the engine schematics it looks like a job pulling the engine and dropping the oil pan/lower section of the engine. Ill try pulling the carb this weekend to see if I can find anything there first.
> 
> Thanks,


 Welcome to the Forum, Hope its the carb and not the govenor.


----------



## dangeroustoys56 (Jul 26, 2010)

Double check and make sure the throttle linkage still has its spring hooked up - the throttle is hooked to the governer under the 'throttle cage' - oddly the 14.5HP OHV briggs is doing almost the same thing on my '97 MTD mastercut ( not original motor) - i need to check that out as well, havent had time( i have other tractors to mow with).


----------

