SoCal Jet Boats
Tech Talk => Jet Pumps => Topic started by: Eswarbrick on August 13, 2019, 04:14:03 PM
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Background info:
Boat is a 76 Baja, 460 ford, 12JE-A pump. I traded for a 95 blazer with a blown transmission. Many things on the boat were unknown to me.
Tried starting the engine and got a horrible squeal as soon as it fired, seemed to come from the jet pump. So I pulled the engine to inspect.
I could not rotate the pump by hand but could with a pair of vice grips and a rag. I thought for sure the thrust bearing was shot but after spraying some penetrating oil into the packing seal everything freed up.
Now there is no noise and the shaft turns easily and quietly. So I’m thinking maybe the grease zerk is bad and was not being properly maintained.
My thinking is that I can pull those seals out with a scribe and install new ones.
My question is, can this be done without removing the shaft?
I see in the Berkeley videos than they are installed after the shaft is in but not all the way in.
With the shaft all the way in, can these be replaced? I was thinking maybe someone has done this before and could shed some light. What’s the best way to extract the old ones?
Thanks in advance, I’m new to jet boats, this is my first.
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Background info:
Boat is a 76 Baja, 460 ford, 12JE-A pump. I traded for a 95 blazer with a blown transmission. Many things on the boat were unknown to me.
Tried starting the engine and got a horrible squeal as soon as it fired, seemed to come from the jet pump. So I pulled the engine to inspect.
I could not rotate the pump by hand but could with a pair of vice grips and a rag. I thought for sure the thrust bearing was shot but after spraying some penetrating oil into the packing seal everything freed up.
Now there is no noise and the shaft turns easily and quietly. So I’m thinking maybe the grease zerk is bad and was not being properly maintained.
My thinking is that I can pull those seals out with a scribe and install new ones.
My question is, can this be done without removing the shaft?
I see in the Berkeley videos than they are installed after the shaft is in but not all the way in.
With the shaft all the way in, can these be replaced? I was thinking maybe someone has done this before and could shed some light. What’s the best way to extract the old ones?
Thanks in advance, I’m new to jet boats, this is my first.
Yes, you can R&R the rope seals with the shaft installed. There is a tool, that resembles a corkscrew, but I can't remember the name. I usually use a small screwdriver and/or a scribe.
The zerk is to grease the thrust bearing. Sometimes do gooders will install a zerk in an attempt to lube the packings. I'm not a fan of this modification.
It's pretty safe to say that the packings are not the source of your noise. While you have the engine out, it is a great opportunity to clean, inspect, and pack the thrust bearing. At the very least, I would pull the bearing cap, so you have a better idea of what is going on inside there.
If the packings are not bad, there is really no need to remove them. Remove the packing clamp to see if the rope seals are dried up and burned. Do they leak excessively while underway? Packings are water lubricated and should leak water at a rate of ten drops per minute. If the packings are too tight and don't leak at all, they will actually deform the surface of the pump shaft.
If you have the means to pull the impeller, a full inspection would be best. Check the bowl bushings and the thrust bearing for excessive wear. Verify that the shaft is not bent. My guess is that the impeller is making contact.
A thrust bearing failure can get super expensive. The suction housing itself is expensive as is everything related to resetting an insert pump. Most importantly, if the pump shaft bottoms against the driveline and pushes the crankshaft, it will cause a catastrophic engine failure.
Good luck,
Joe