Outboard block cracks

[Engrguy]

I'm repairing a '75 Mercury 1150 (in-line 6) Outboard due to burned piston in #1 cylinder. I disaasembled the powerhead and upon inspection of block and cylinders found cracks in the alum block between cylinders 3,4 & 5 right where the locating pins for the main bearing/reed cage are located. Have any of you emcountered this before? Is it repairable or is it scrap? I have a close-up photo available if it would help.

 

[Laddies]

Re: Outboard block cracks

We have seen it in some of our racing engines, there was a tool shop in our area that use to repair them for us. they would weld the hole and crack shut, ck the bore and clean if it needed it and redrill the hole. We found by using locktite 518 on the blocks it has stopped the problem. I wonder on a normal engine if Devcon or some other good grade of epoxy filler wouldn't work--Bob

 

[Clams Canino]

Re: Outboard block cracks

I've seen it before too. A good machine shop outta be able to fix it. I'm thinking that some locktite on the little blocks and getting the intake cover shaved by a couple thousanths outta create a situation where those blocks cant move at all - with or without pins. (but put the pins in)<br /><br />Also, you can drill deeper and use longer pins, not for the squeemish. <br /><br />If you don't beat on the motor it outta do just fine. The blocks weren't the reason #1 burned, so if you hadn't had to go in and see them. <br /><br />-W

 

[Engrguy]

Re: Outboard block cracks

Thanks for your responses. You've given me hope that the block is still useable. I'll will be contacting some shops in my area about doing the repair. I have some concern about distortion due to heat from welding. It's such a narrow section between cylinders. Do you think the sleeves will be OK? <br /><br />I couldn't see a connection between the burned #1 and the cracks around the pin locating holes either. Any thoughts on the cause of these cracks? <br /><br />Thanks