Looper Shutdown with a rattle noise

[spareparts]

check the flywheel nut, make sure the flywheel is tight. I had a merc that was making rattling noises, found out the flywheel was loose, had to replace the flywheel.

[nymack66]

Ok I will check tomorrow..

[THEFERMANATOR]

You need to find where your compression was leaking. Broken reeds will not cause low compression unless something is jamming them closed and not allowing any air past.

[nymack66]

Please see the flywheel photos on this link http:\\www.nymack66.com
As for the flywheel been loose I will check since I did pull it off last year !
What is the correct procedure for a compression check I disconnected the fuel line remove left 3 plugs in and connected to one cyl crank the engine about three turns. Is this correct?

[Skools Out]

9 amp charging so not a magnet issue. you could pull the carbs and look at the reeds or heck pull the reed body and look in the cylinders and turn by hand till each rod is at the hole then rock to see if you have a bad rod bearing or loose rod cap. those rod caps use either a 5/16 or 8 mm 12 point socket. must be a 12 point. you can check the torque of the rod cap bolts threw the reed holes as well. that 12 point 8mm is avail. at sears.

[nymack66]

Guys,
Why is it the pistons are really loose ? Is this normal ? Is it possible the previous owner installed the wrong set of pistons in a re-bore sleeves?

[Steplift 72']

Originally Posted by nymack66

Guys,
Why is it the pistons are really loose ? Is this normal ? Is it possible the previous owner installed the wrong set of pistons in a re-bore sleeves?

The pistons should not be "really loose" but they will slighly rock. I had a rattling 86' model 140 looper that still had 125 pounds of cranking compression. It turned out that a series of motors in 86' had carbs that ran the motors too lean, mine was one. In the first 6 months it had lost 400 rpm and sounded terrible. The piston tops and cylinders looked perfect but the lean running had worn the motor out in a couple hundred hours.

[THEFERMANATOR]

85 had ALOT of problems with the 140, and 86-early 87 did as well as far as carbs go. If you run the VRO they aren't too bad, but if you pre-mix it makes it worse MUCH WORSE! I spent several days re-jetting my carbs after I swapped from the early style 140 carbs used in 85 only to those that were used in 86 and the first of 87. The domes will be loose, but it's the skirt you have to worry about. If the piston skirts are loose the engine could have decent compression and still not idle. I was gonna mention that your pistons looked awfully loose from your pics, but it's hard to judge from pictures if they are too loose or not. OMC issued a bulletin though to jet up 2 sizes in the mains on the early loopers as the aggressive porting in them caused ALOT of lean out issues.