Crankshaft Driven Water Pump Problems

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   I installed a Sherwood P105 crankshaft driven water pump on my OMC 350 last spring. It always had a wiggle when at low RPM and seems to have a slight vibration at higher RPM's. I did not think this was a good thing but could not think of a method to solve it? Well the weather got nice so I just ran it!

Guess what happened? I was crossing over to Put-in Bay in Lake Erie on Saturday with 3 to 5 foot waves and lots of wind, with about 4 miles to go, I started to hear a screeching sound and looked down at my gauges. The amp meter was swinging back and forth with every screech! Not a good time to stop and trouble shoot, motor still running so we kept on heading to calmer water. Once I made it to smoother water I opened the engine cover and my water pump was spraying water out the shaft seal directly onto the alternator belt.

Well I got out the electrical tape and taped up the opening to let the water drip down into the bilge rather onto the alternator belt. Ran the rest of the weekend without incidents other than the carburetor (save that for another post).

I have ordered a replacement seal for the water pump but I am looking for advice on how I can balance this pump connection to the crankshaft so that it does not wobble. Any ideas?

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2_Nautiques Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: March-22-2006 Location: United States Status: Offline Points: 251	Post Options Post Reply Quote 2_Nautiques Report Post Thanks(0) Quote Reply Topic: Crankshaft Driven Water Pump Problems Posted: July-18-2007 at 4:52pm
	I installed a Sherwood P105 crankshaft driven water pump on my OMC 350 last spring. It always had a wiggle when at low RPM and seems to have a slight vibration at higher RPM's. I did not think this was a good thing but could not think of a method to solve it? Well the weather got nice so I just ran it! Guess what happened? I was crossing over to Put-in Bay in Lake Erie on Saturday with 3 to 5 foot waves and lots of wind, with about 4 miles to go, I started to hear a screeching sound and looked down at my gauges. The amp meter was swinging back and forth with every screech! Not a good time to stop and trouble shoot, motor still running so we kept on heading to calmer water. Once I made it to smoother water I opened the engine cover and my water pump was spraying water out the shaft seal directly onto the alternator belt. Well I got out the electrical tape and taped up the opening to let the water drip down into the bilge rather onto the alternator belt. Ran the rest of the weekend without incidents other than the carburetor (save that for another post). I have ordered a replacement seal for the water pump but I am looking for advice on how I can balance this pump connection to the crankshaft so that it does not wobble. Any ideas?
	1988 Ski Nautique

backfoot100 Members Profile Send Private Message Find Members Posts Add to Buddy List Platinum Member Joined: January-03-2007 Location: United States Status: Offline Points: 1897	Post Options Post Reply Quote backfoot100 Report Post Thanks(0) Quote Reply Posted: July-18-2007 at 5:26pm
	Matt, I have the crank driven Johnson pump on my 350 Indmar but the mounting flange should be the same. I can only speak from experience on mine but the pump drive flange that attaches to the crank pulley can only go on one way . . . correctly. It fits a couple other ways incorrectly but it does still go on. Mine is attached with three bolts in the crank pulley, but I seem to remember that there is another hole or a cutout on the edge of the flange (I think) that needs to be properly positioned around another bolt or key or something else that protrudes in the crank pulley. I too struggled with that a few years ago when I removed and replaced the pump and I had a hell of time getting that thing to go on properly. Once it's on the right way, you'll likely kick yourself in the ass. Now, you'll still get a little bit of wobbling of the pump when installed correctly, but nothing like I'm sure it's wobbling right now. Let me know if you still have any issues and I can snap a picture of mine (if I can get a good enough shot) and post it for you. Feel free to call me with questions. My cell is 407-733-3599. 95% of the guys on this site are running the pulley driven RWP that is factory equipment from PCM so they would not be much help to you.
	When people run down to the lake to see what's making that noise, you've succeeded. Eddie

2_Nautiques Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: March-22-2006 Location: United States Status: Offline Points: 251	Post Options Post Reply Quote 2_Nautiques Report Post Thanks(0) Quote Reply Posted: July-18-2007 at 6:03pm
	Eddie, I know what you mean about the bolts and what appears to be large roll pins or tubes sticking out of the crank shaft. There are holes in my pump flange to go over those pins and it seems to line up OK. Maybe I just have a bad seal. I am glad to hear that yours has a slight wobble, maybe mine is OK, I just thought that it would run perfectly true. I to am more familiar with the belt driven pumps. I though about putting a gasket of some type between the pump flange and the drive shaft and tighten the bolts alternatly until it runs true, just not sure if that is the right thing to do? Thanks for your input and offer to help.
	1988 Ski Nautique

backfoot100 Members Profile Send Private Message Find Members Posts Add to Buddy List Platinum Member Joined: January-03-2007 Location: United States Status: Offline Points: 1897	Post Options Post Reply Quote backfoot100 Report Post Thanks(0) Quote Reply Posted: July-18-2007 at 6:51pm
	I don't know if trying to put a gasket of some sort would work Matt. I tried to alternately tighten them too. The problem is that you have no idea if it's trued up until you turn it over and then you have to start all over again and you're just guessing if it's true or not. You're also guessing if it's true by alternately tightening three bolts instead of four. The real PIA is trying to work around the pylon!!!! You don't have much room there. I have seen a few other boats in operation with the crank driven pump and they had just a little wobble too. After 1200 hr's on mine, I've had no issues at all. The only reason I pulled it off before was to be able to manually wrench the motor to TDC on #1 cylinder for installing a new distributor. If it wasn't for that, I wouldn't have had to touch it.
	When people run down to the lake to see what's making that noise, you've succeeded. Eddie

2_Nautiques Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: March-22-2006 Location: United States Status: Offline Points: 251	Post Options Post Reply Quote 2_Nautiques Report Post Thanks(0) Quote Reply Posted: July-18-2007 at 7:07pm
	Eddie, you right it would be a pain trying to get it adjusted correctly without a dial indicator or something like that. I don't have a pylon to deal with on the cuddy, however it does extend far enough forward that I am working under a portion of the floor. After talking with you I think I might just have a bad pump. It does have a double set of bearings ahead of the seal so even if it does vibrate the seal still should have held.
	1988 Ski Nautique

Crankshaft Driven Water Pump Problems

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