Scag STT61A-27kw Muffler replacement

[deamer1]

Scag STT61A-27ka FD750 FD Muffler replacement

Hi,
I'm having a difficult time replacing the muffler on a Scag Turf Tiger STT61A-27KA FD 750D Kawasaki engine equipped mower, and need some advice as to how to proceed with this project. This mower has the 27 h.p. Kawasaki engine, model FD 750D.
In the service manual it shows how to replace the muffler with the engine only in the photos. Nothing is shown or described as to how to replace the muffler while the engine is installed on the mower.
The problem for me is that the lower mounting bolts are very difficult (impossible) to access as it is on the mower. There are the exhaust manifold nuts, washers and gaskets which is not a problem at all. Looking at the mower from the rear...I am unable to access the bolts holding the lower mounting bracket of the muffler to the motor chassis.
What I'm looking for is if anyone has experienced replacing the muffler and how did they do it? Loosen the engine from the mounting? Any other good advice you may have for me.

The problem is that the muffler pipes coming from the exhaust manifold into the muffler on both sides have broken at the welds completely around the joints. I need to get the muffler off to repair the joints or replace the muffler. NEED HELP PLEASE!

Deamer1

 

[BlazNT]

The muffler mounts to the bottom side of the engine. Looks like engine removal is probable.

 

[deamer1]

Hi Blaznt,
Thanks for the response.
I've finally figured it out. Your correct in that engine removal procedure is most likely needed. I've removed all the bolts holding the engine in place except one which is difficult to get a wrench or socket on it. Still working on that one...it's a 17 mm. I'm being cautious as to not round off the corners of the bolt head and then have a greater problem. Have had it soaking with penetrating oil overnight.
It appears that once the eight bolts holding the engine in place are removed, the engine can be moved forward just enough to get to the mufflers lower mounting bolts. It may be a "knuckle buster", but appears it is possible.
This is one of those repairs which would take a very short time to complete, IF everything was easy to access, and you didn't have to remove all the other items to complete the muffler replacement. But it is what it is, so I'll scrape a few knuckles and get it finished.
Thanks again for the input. Enjoy your week.
Deamer1

 

[BlazNT]

Take pictures of belts before you remove them. You will thank yourself for it.

 

[deamer1]

I did take pictures as I do most every time. They rescue me from a bad memory! :confused2:
Thanks for the input. I'm tackling it again today.

 

[deamer1]

After quite some time fussing with this project, and even more time studying the Service Manual, I'm on my way to putting it back together.

It's almost a given that you must loosen the engine mounting bolts (eight each) to access the two bottom bolts holding the muffler to the lower rear engine water pump area. I did this and found that the engine although it may be heavy weight wise, it's easy to move around on the mounting tray. I pried it up approximately two-three inches and used wooden carpenter wedges to elevate the engine. This gives you access to the mufflers lower mounting bolts.
(13 mm )size.

I removed the muffler, ordered new exhaust manifold gaskets along with some other misc. items.

I began the new muffler install which was fairly easy to complete. It's easier to leave the engine in a raised position until the muffler install is completed, then lower it down on the mounting plate and slide it into position and install the eight engine mounting bolts. Removing the clutch from the rear of the unit gives quite a easy access to the engines rear mounting bolts. It is possible to remove the engine mounting bolts without removing the clutch, but it's far easier with the clutch removed. Removing the clutch consists of removing one bolt, unplugging the units wiring plug and sliding it off the drive shaft. It installs very easily.

Prior to quitting for the day...I have the new muffler installed on the engine, the clutch re-installed, the engine mounting bolts installed. Will continue to put it back together tomorrow.
I'll add something here when I get it back together and tested.
Deamer1

 

[BlazNT]

Glad to hear it is going so well.

 

[deamer1]

It's been a learning experience for me, but a good one. The machine is back together 100%. The muffler repairs seem to be a "MAJOR" repair at first, but when you break it down to small steps...it isn't that complicated. :confused2: Just takes time, Also saves a huge shop labor bill. :thumbsup:
Deamer1