1gm yanmar impeller change

[jfschena]

I'm expecting delivery Wednesday of my "new" 1984 oday 26. I'm planning to change the impeller first thing. I noticed the plate is partially blocked by the alternator pulley and is installed with screws. This would mean pulling the pulley first. The yanmar book shows this plate installed with bolts. A wrench could fit behind the pulley. It might be way easier to take off the whole water pump and change the impeller that way. Any thoughts?

Joe

 

[Alan Gomes]

I'm expecting delivery Wednesday of my "new" 1984 oday 26. I'm planning to change the impeller first thing. I noticed the plate is partially blocked by the alternator pulley and is installed with screws. This would mean pulling the pulley first. The yanmar book shows this plate installed with bolts. A wrench could fit behind the pulley. It might be way easier to take off the whole water pump and change the impeller that way. Any thoughts?

Joe

I have a 1GM and the standard Yanmar raw water pump as I presume is on your boat. There is no need to remove the pulley or the pump. You can get at the screws easily with the appropriately sized wrench. If I recall, it is only something like 7mm, but I could be wrong about that.

Once you get the cover off, you may find the impeller a little tricky/awkward to install just because it's so tiny on that little pump. But you'll get it easily enough if you just persevere. One trick that might help (which I'll try next time) would be to use a small plastic wire tie around the impeller vanes, to bend them in the right direction and make insertion of the impeller a bit easier. Install the wire tie so it is toward the front of the impeller (i.e., toward the front of the engine). Then, as you push the impeller on the shaft, the wire tie will slide forward and off of the impeller.

Also, I found that with the paper gasket alone it leaked slightly. I applied some gasket sealer on both sides of the paper gasket and the problem was solved.

--Alan Gomes

 

[dparilla]

If my memory serves, the 1 GM's raw water pump is belt driven, but you should not have to remove the belt to change the impeller.

There should be no reason you can't switch to bolts vice screws to make plate access easier, but just be sure not to "over torque" them when re-installing. I would not however take the pump off to change the impeller.

 

[Alan Gomes]

If my memory serves, the 1 GM's raw water pump is belt driven, but you should not have to remove the belt to change the impeller.

There should be no reason you can't switch to bolts vice screws to make plate access easier, but just be sure not to "over torque" them when re-installing. I would not however take the pump off to change the impeller.

No, the pump is not belt driven.

--Alan Gomes

 

[jfschena]

Thanks, I guess I'll have to use a small vice grip or other similar tool to get that one screw off. There's no way that I can see to get a screw driver in there. When I reinstall I'll use bolts.

Joe

 

[jfschena]

Btw, I've seen on the Internet a recommendation to coat the impeller liberally with Vaseline before reinstalling, any thoughts on this?

 

[Alan Gomes]

Thanks, I guess I'll have to use a small vice grip or other similar tool to get that one screw off. There's no way that I can see to get a screw driver in there. When I reinstall I'll use bolts.

Joe

I don't recall just what the clearance is to the pulley, but perhaps you could use one of those small 90-deg. angle ratcheting screwdrivers to remove the one offending phillips head bolt. (Example: http://www.harborfreight.com/8-piece-right-angle-screwdriver-92630.html) I don't see why vice grips wouldn't work in a pinch, though (pun intended). Replace the bolts then with hex heads and it will be a cinch to remove in the future with a small wrench. As I mentioned, if I recall correctly I use a 7mm wrench to remove mine.

--Alan Gomes

 

[Alan Gomes]

Btw, I've seen on the Internet a recommendation to coat the impeller liberally with Vaseline before reinstalling, any thoughts on this?

It wouldn't hurt to coat the inside of the pump with Vaseline or (better) some teflon grease (like SuperLube), though I don't think it's essential. Just spread a bit around the inside of the pump--no need to go crazy with it. This will be good for the impeller for those first seconds where it is running dry while the pump primes--though a few seconds of dry running isn't going to hurt anything anyway. I suppose the grease will also help the impeller slide in with a bit more ease.

 

[Canonshooternb]

I have the same issue and don't know how to go about removing that difficult screw without stripping it. Once removed they will be replaced with new bolts instead.
Can anybody explain how to get at and remove the screw.
My next task is equally difficult in removing the bolts on the zinc cover. Just as obstructed

 

[Alan Gomes]

I have the same issue and don't know how to go about removing that difficult screw without stripping it. Once removed they will be replaced with new bolts instead.
Can anybody explain how to get at and remove the screw.
My next task is equally difficult in removing the bolts on the zinc cover. Just as obstructed

Regarding changing the zinc: This is easy enough to get to once you remove the alternator. The alternator, in turn, is not difficult to remove. Realistically you can remove it in a couple of minutes. Just make sure that you check carefully for leaks after you replace the the zinc.

--Alan Gomes

 

[Canonshooternb]

I thought the Alternator would have to come off, thanks for confirming it.

Do you know of an easy way to ge the difficult screw from the water pump cover ?

Paul

 

[Alan Gomes]

I thought the Alternator would have to come off, thanks for confirming it.

Do you know of an easy way to ge the difficult screw from the water pump cover ?

Paul

Did you look at this tool that I mentioned in my earlier post?

http://www.harborfreight.com/8-piece-right-angle-screwdriver-92630.html

I think there may be enough room for it to fit, though I can't say for certain. Otherwise, needle-nose vice grips should do the job.

--Alan

 

[jfschena]

Thanks for the tool tip. A far more elegant solution than vice grips.

 

[jfschena]

Update. Got the boat today. The tool from harbor freight is too big. I'm going to try and cut down the bit with a dremal tool so it will fit behind the pulley. . . . . Stay tuned for updates

 

[Alan Gomes]

Update. Got the boat today. The tool from harbor freight is too big. I'm going to try and cut down the bit with a dremal tool so it will fit behind the pulley. . . . . Stay tuned for updates

Or perhaps a grinder would make short work of that screwdriver bit.

Either way, we await your update with great anticipation!

 

[jfschena]

here it is

 

[jfschena]

Got the cover plate off. The next issue is converting to hex head bolts. I can't seem to find brass, m4 .70 6mm screws anywhere. I've been to 2 fastener companies and a marine place and a couple of different hardware stores. Nothing. I called torrenson and all they have are Philips head. . . .

 

[Alan Gomes]

Got the cover plate off. The next issue is converting to hex head bolts. I can't seem to find brass, m4 .70 6mm screws anywhere. I've been to 2 fastener companies and a marine place and a couple of different hardware stores. Nothing. I called torrenson and all they have are Philips head. . . .


View attachment 64121

Congrats on getting off the cover. You are nearly home free!

I just got my new screws at my local Captain's Locker. I believe they are stainless, though.

 

[Fred Villiard]

Try mcmaster.com

Fred Villiard

 

[jfschena]

I'll do that Fred. Thanks. Are their any corrosion issues mixing stainless and brass? I did find stainless.