Covers off. One exhaust push rod out of place, but it appears in good shape. Lot of play in rockers but idk what’s normal. Other rockers intact and valves move. Researching.
kbowley
Well-Known Member
- Joined
- Jun 8, 2011
- Threads
- 2
- Messages
- 123
Did you check both cylinders? The valves need to be adjusted while you have the cover off. Valve clearance is about .003 for intake and .005 for exhaust. This needs to be checked on the compression stroke. You can use a small screwdriver through the spark plug hole to feel the top of the piston movement as you rotate engine. When the piston comes up to the top of travel and just as you very slowly rotate the engine until the piston begins to go down VERY slightly. Feel both rockers to be sure they are loose then set the clearance with a feeler gauge. it may take multiple times to get them right. You can find YouTube videos to show you how to do it. If you are unsure, bring it to a shop and have it done. However, the rocker falling off will not cause low or no compression since the valve stays closed with the rocker arm off. Are you sure your gauge is working correctly?
kbowley
Well-Known Member
- Joined
- Jun 8, 2011
- Threads
- 2
- Messages
- 123
The OP stated that one of the rockers popped off the pushrod. However, that would mean that the compression should be okay since the valve remains closed. So, you have a good point HLW49, it could be both rods. However, in most cases, the engine will not rotate smoothly if the rod(s) have failed, or it will make a noise while doing so. We shall see when he adjusts the valves using a screwdriver on top of the piston to get TDC.
You were right unfortunately. Both rods gone. Bent camshaft. Scarred crank.
Thanks for all the feedback. I got it all opened up because pistons weren’t moving. Both rods gone, bent camshaft, scarred crank. It ran fine till it didn’t. Had high hours and probably hot because covered with more crud than it should’ve been. I got it used this year. Did not get my money's worth. Gonna llook up part costs, motors, etc.
- Joined
- Feb 19, 2020
- Threads
- 91
- Messages
- 11,476
Probably was only running on one cylinder and then the second rod failed. I even one engine with one broken rod and a large hole in the crankcase the customer was still using but brought it in complaining of low power.
kbowley
Well-Known Member
- Joined
- Jun 8, 2011
- Threads
- 2
- Messages
- 123
If it is in decent shape otherwise, I would try to source a replacement engine. Those are pricey machines new. A new Briggs twin will run you roughly 1k with shipping...your local husky dealer may save you some after all told, maybe not. Be sure to get a 16-amp alternator and fuel pump. It would be okay with a 9-amp alternator as well. There is a gent local to me that has tons of used engines but if you can swing, I would go new if the machine is in decent shape, otherwise, try to source a used I/C series or Endurance series. The decision is yours as to weighing the options. A new engine is still cheaper than buying a used MZT. You can try Smallenginewarehouse.com and they can sell a drop in, not sure of the price, give um a call. A 40 or 44 cubic inch is plenty of power to run it well.
bertsmobile1
Lawn Royalty
- Joined
- Nov 29, 2014
- Threads
- 65
- Messages
- 24,995
I have an engine in the workshop that only had 1 rod in it from new
Customer brought it in for a service complaining that his 18Hp twin had less poke than his on 10Hp single .