Mercruiser mc 1 question

[danield]

With help from another member my drive was identified as a mc 1, seems there are two types of mc 1s, one with flush screw in lower unit, and one with out the flush screw. My question today is facing the drive while on boat (right side) of lower unit there is a hole, but there are no threads in the hole, is this where a flush screw is supposed to be or just a drain hole, I pulled the unit today and the impeller was toast it has a number in the base of the pump which is 46-57234, when I researched that number it is a base for mc 1 without flush hole, so is the hole in my lower unit just a drain hole, or is there supposed to be a plastic screw in there, like I side it is not threaded. again any help would be greatly appreciated

 

[achris]

Re: Mercruiser mc 1 question

Very early MC-1 drives had the flush hole (hang over from outboards). The later ones don't have the flush hole.

The hole you're referring to... Down lower right at the front of the drive?, or up above the anti-cav plate, where it would go into the base of the water pump?

If it's the drain hole at the bottom, it NEEDS to be free and clear to flow water. If the cavity inside the drive is full of crud (not unusual) you need to clean it out. Don't plug it up.

Chris.......

 

[haulnazz15]

Re: Mercruiser mc 1 question

Need a pic of the hole you are referring to, or at least a better description of where you are looking at. There is a very small hole toward the nose of the drive (on both models) that is a drain hole for the cavity in front of the lower shift shaft. As achris mentioned, it needs to be free and clear in order to drain any water to avoid it getting trapped and freezing in the colder months. The flush attachment on the early MC-1's is closer up to the cavitation plate.

 

[danield]

Re: Mercruiser mc 1 question

can't get pic right now but the hole i'm speaking of is on the lower drive unit actually lower then the prop shaft

 

[Bt Doctur]

Re: Mercruiser mc 1 question