Stripped phillips head on impeller cover.

[Rperlot]

I'm trying to replace my impeller. As with any boat project, something that should be 15 minutes has become impossible. Two of the screws on the impeller cover are rusted out and I can't, for the life of me, get them off. I've stripped the screw heads by now.

Does anyone have any tricks to get a screw out in a tight space? I've tried to use an easy-out, but the exhaust box is about 1.5" from the screw head and I can't even fit the easy-out in the gap. It is only big enough a gap to get a ratchet style screw driver into.

Once successful, I am replacing with hex heads.

Also, if anyone has a name for that metal shim in the impeller housing that the impeller wears against. It is removeable, probably because it wears down over the years. I can find the impeller and gaskets parts, but that shim probably also needs to be replaced after nearly 25 years of wear. I don't even know what its called. A source for the parts would be much appreciated.

Rperlot
CD28 #352

[Jerry Hammernik]

If you can get the old wreckage out you really should switch to the Speed Seal. It has four knurled thumb screws and an o-ring seal. I really like it. It's the answer as far as I'm concerned. Good Luck.

[Kittiwake]

Last summer I had similar problem, although I was lucky and simply broke the head off the screw. We ended up taking off the whole unit that impeller sits in, got the screw off, and replaced it with a Speedseal. The Speedseal unit has made it very easy to replace the impeller, you can do it without being able to see the knurled nut heads. Currently replacing the riser, muffler, and exhaust system. That will allow even easier access to the back end of the MD7A. After spending 2 days upside down under the cockpit, I feel like I finally have an idea what the back end of the MD7A looks like! Not the best time, but worthwhile.
Peace and Fair Winds, Bill

[pedbed]

The small piece you refer to is a cam.

I would agree the best thing to do is remove the entire pump from the engine.

It would be a good time to replace the two seals that keep oil in the engine and water out.

Then you can either get a speed seal cover or get two replacement brass screws.

A right angle screw driver works best for removing these screws.

Good Luck.

[Carter Brey]

Rperlot,

That part you ask about is the cam. It is removable and should be replaced if it's scored or if the edges are razor sharp.

Don't despair, you'll get the thing off with a little ingenuity. You might want to arrange a hierarchy of solutions in your head, from least to most destructive.

Which engine do you have? A Volvo?

Have you tried spraying the offending screws with PB Blaster? Since the Phillips head slots are stripped, perhaps you can get a vise grip on the screw heads to turn them after letting them soak for a day with occasional tapping.

If that does not work, and you must remove the screw heads, a surprisingly effective tool is a certain hand saw that incorporates an ordinary hacksaw blade which extends a few inches past the handle. It's great for slicing off things in tight spaces where the water muffler prevents easy access (ask me how I know). It sounds as though there's not enough room to get a Dremel tool in there, even with a right angle attachment; besides, you don't want to be making sparks in there.

The Speedseal is a great idea for when you finally get the cover off.

Good luck,
Carter

[Rperlot]

I'll look in the PB Blaster. Seems this is the next escalation step.
Maybe I could use a dremel to cut the easyout and use a vise grips as the handle to try again.

Vice grips on the screw next, as this will probably end badly and need the whole pump to be taken out.

I think I could get to it with the dremel comeing from top or behind using either the 90 degree attachement or the carvers attachment and a cutoff wheel. But I'm sure this would also lead to needing to pull the whole pump as I'm not confident I could get the stub of the screw out.

Does the pump have clearance to be removed in whole without obstruction by the exhause box?

I too need to replace the exhaust box anyway as it has a leak, but I looked at the bolts holding the mounting bracket to the reverse gear and I don't know how I could get a wrench around them without reming the motor so I can get an open end to it from underneath. I had thus, intended to wait until winter and use a cutoff tool to cut the box around the base and use the base as the mounting for the new box. I would be very interested in the detail of the exhaust box project.

Does anyone have sources for the bearings, o-ring seals and cam?

Sincerely,
Rich.

[Rperlot]

dd

[Oswego John]

Rich,

Is it at all possible to get a Dremel tool with a 90° adaptor in position to work on the cover screws? If so, use a cut off wheel and try to create a slot in the screw head that will accept an angle head screwdriver with a flat blade.

As for the exhaust box mounting bracket bolts, do you think that a crowfoot socket might work to remove them?

Just some thoughts.

O J

[Stan W.]

Pump is Johnson. Johnson still leading manufacturer. Parts available through decent chandlery. Need model no. Believe to be 858065 but confirm your pump. One source:

http://www.marinepartsexpress.com:8080/ ... our&ID=320

[Dean Abramson]

Try coming at the heads at a 90 degree angle with a small vise grips. That's what I did. The I bought a SpeedSeal cover.
Dean

[Michael Abramson]

Although I have not bought from them, I did get some prices from DB Marine in the UK for various MD7A parts. They were less than USA prices by a good margin and a small part like that could easily be mailed.

Send them the specific engine number with your email so they can look up the exact part needed. You will get better results by providing as much info as possible.

www.dbmarine.co.uk

Michael

[Kittiwake]

On Kittiwake (CD "28" #317) with MD7A, originial muffler, etc, the water pump was removable without removing anything else. There were 2 of us to do it, so a little bit easier to get wrench on bolts, etc.

Removing the muffler was alittle bit bigger deal - the 4 bolts holding riser to exhaust manifold were all accessable with either socket or open end wrench, although the fuel filter had to be removed to get one of the inboard bolts. Might have been able to get it if I had a thin wall socket. The 2 bolts holding the muffler bracket to transmission were also accessible. Had to find the cotter pin holding transmission cable connection in order to finish removing the muffler, that was the long process - finally found that it could be accessed from the front, once the muffler was moved some. The whole process took about a day and a half, with a lot of breaks for water, to look at things, etc. Let me know if you have questions.
Peace and Fair Winds, Bill