1350 1971 Overhaul

[OperativeK]

This week I am having my cylindars/cylindar bored out since somehow I had lost the top ring on several of my pistons. My question is this even though I could only see and feel damage scoring on one cylindar would it make more sense to bore all cylindars and will it cause any problems just doing a single cylindar over and not the rest?<br /><br />Im guessing that maybe on a V model motor it might cause some type of problem but on an inline that this may not be an issue? <br /><br />I couldn't believe there wasn't more damage to the motor considering the lost of the top ring on three pistons. I could see pot markings on the top of the cylindars of each and should that be a concern?, none seemed to be very bad. Im very curious as to how this would happen all the other rings looked great. On one piston it still had a small segment of ring left and it looked more as if it had corroded in some way.<br /><br />Last item is after I pulled the head off the lower unit I pulled up on the shift lever and took it out. But now when I put it back in the lower unit I can't seem to shift either into forward or reverse. I have already removed the LU during impeller replacement what do I need to do to get the gear shift shaft back in correctly?<br /><br />Thanks fellas and Ill be calling Clams today with my order as soon as the guy at the shop has a look at the cylindars and depending if he recommends I bore over on more than the single cylindar.<br /><br />-Mike

 

[emckelvy]

Re: 1350 1971 Overhaul

There is no need to bore out any more cylinders than what is necessary to correct scoring or out-of-round/taper. It's a waste of money to bore all of them just because one is bad.<br /><br />I just tore apart 2 M800-4 powerheads. Both had some degree of ring breakage/piston destruction on one cyl and neither had cylinder damage. Although one of them had lots of pound marks on top of the cylinder!!! Just the Luck of the Mercury Gods that the pieces roll around and get spit out of the exhaust ports without damaging the cylinders.<br /><br />Don't worry about the divots in the top of the cylinder, as long as they haven't busted anything. Just make sure there's no 'chunks' left!<br /><br />Regarding your lower unit problem, as soon as that shift shaft pulled out of the lower unit, the shift cam was pushed out of position by the spring-loaded shift clutch.<br /><br />The only way to get the shaft back in properly without dismantling the lower unit is to remove the pre-load pressure on the shift clutch, and 'jiggle' the shift cam back into alignment.<br /><br />You'll first need to flush all oil out of the gearcase so you can see what's going on. Recommend you drain the oil then use a little kerosene or similar mild solvent (even WD-40 would work since it's mostly kerosene anyway) to wash down the oil. This is so you can see the cam move.<br /><br />Then, rotate the propshaft clockwise. As you turn it, you'll feel the spring tension increase as the shift clutch 'walks' up the ramps on the forward gear, then 'pop' as it falls off. Just before the 'pop', all of the spring tension on the shift clutch is relieved. At this time the shift plunger in the end of the propshaft is no longer pushing on the shift cam.<br /><br />With the shift shaft bushing removed, peer down the hole with a strong light. "Jiggle" the lower unit around and you'll see the shift cam moving about. Re-position the shift cam such that its splines are centered in the hole and you'll be able to re-insert the shift shaft.<br /><br />You'll know when you've got it right because the shaft will go down further, it'll be engaged into the cam and the lower unit will now shift.<br /><br />Now you owe me a 6-pack of Pepsi One for revealing the Secret Shift Shaft Reinstall Method!!! <br /><br />HTH & G'luck.........ed

 

[OperativeK]

Re: 1350 1971 Overhaul

Thanks Ed, Ill give it a shot when I get home today.