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Craig
05-18-2009, 10:33 AM
I believe the pulley on my LT1 is stretching out belts due to a wobble.

The raw water pump is visibly wobbling a considerable amount and it the pulley is wobbling some too but not quite as much (as far as I can tell subjectively anyway).

There are no drips or other leaks from the circulation pump or raw water pump and the motor is staying nice and cool. The biggest issue (currently) is that I cannot maintain belt tension so the belt squeaks on startup.

So three questions:

1) I am guessing that there is a bad bearing somewhere anyone have any ideas if it is a circulation pump or raw water or do I need it pull it apart and check both?

2) Also, can you get replacement bearings or do I need to replace the whole unit?

3) Finally, is the circulation pump in an LT1 the same as the standard 350? I know the raw water pump is different.

Thanks all

Andyg
05-18-2009, 11:48 AM
I had a 1997 190 with the LT-1 and had a similar problem. I doubt you are actually stretching belts. Have you compared a new belt to one that you have run on your engine? There are a couple of things that I think you need to verify. The culprit in my case was a bad belt tensioner pulley. It is the pulley that is spring loaded and keeps tension on the belt. At the same time I discovered that the tensioner pulley wasn't working I also noticed that I had a broken mounting bolt on my alternator. I would check to make sure neither of these are what is causing your problem.

Andyg

AFX-30
05-18-2009, 12:06 PM
I had a 1997 190 with the LT-1 and had a similar problem. I doubt you are actually stretching belts. Have you compared a new belt to one that you have run on your engine? There are a couple of things that I think you need to verify. The culprit in my case was a bad belt tensioner pulley. It is the pulley that is spring loaded and keeps tension on the belt. At the same time I discovered that the tensioner pulley wasn't working I also noticed that I had a broken mounting bolt on my alternator. I would check to make sure neither of these are what is causing your problem.

Andyg

Alonf with all of the I pulled my raw water pump off the other day and the three bolts that hold it to the crank shaft had come loose. I would ck those also.

Craig
05-18-2009, 12:28 PM
I had a 1997 190 with the LT-1 and had a similar problem. I doubt you are actually stretching belts. Have you compared a new belt to one that you have run on your engine? There are a couple of things that I think you need to verify. The culprit in my case was a bad belt tensioner pulley. It is the pulley that is spring loaded and keeps tension on the belt. At the same time I discovered that the tensioner pulley wasn't working I also noticed that I had a broken mounting bolt on my alternator. I would check to make sure neither of these are what is causing your problem.

Andyg

I actually do not have a tensioner. I have an adjustable bracket on my alternator, to apply tension I get a large pry bar and pull on the alternator while having another person tighten the bolt on the alternator.

I did look over the alternator pretty well, I will double check to make sure this isn't the problem.

I will also check the bolts on the raw water pump.

Thanks guys, I appreciate the input; if anyone else has thoughts I would love to hear them :)

Craig
04-23-2010, 07:17 AM
Just an update.

This problem continued to linger throughout the remainder of last season. I got the belt tightened up enough that it wasn't squealing at all but it still seemed like a lot more wobble than I should have. My buddy, who has a 205 with an LTR, also seemed to think the wobble was a bit much but nothing he would worry about.

Well, now the wobble is bad enough this year after the lay up that I sheared the bolt off of the L-bracket that attaches to the bottom of the raw water pump. The bolt stuck in the bottom of the raw water pump. I noticed it because I heard the bracket dangling around hitting the pump during acceleration. At first I thought the bolt had vibrated loose but on further inspection it sheared that sucker right off.

I am guessing it is either the bearings in the raw water pump itself or maybe in the circulation pump? Are these on the same shaft?

Anything I am missing that I should check out?

1redTA
04-23-2010, 08:51 AM
The water pump on my lt1 car is driven by the camshaft. I figured they would have the same pump I know the opti less ignition is nice

Tom Jones
05-03-2010, 08:12 PM
i had the same issue with my 1994 LT1
it turned out the be the harmonic balancer
got it replaced and it was cured
with mine there was a vibration in the engine driveline also

EricB
05-06-2010, 10:00 PM
The circulation pump on an LT1 is driven by the camshaft. Therefore it will have no effect on the wobble you are experiencing on the raw water pump.
First (easiest) thing to do is remove the raw water pump and inspect for loose shaft and/or retainer hardware. Also, when was the impeller replaced? Check it for some missing vanes.

Craig
05-07-2010, 10:11 AM
I pulled the pump off last week and found no play in the bearings and they turn smoothly, it has never leaked so the seal is good as well. I was surprised, but the pump is really in perfect functional condition.

The impeller was brand new at the beginning of last season. I pulled it out as well and looked it over, looks almost new and still plenty flexible.

My current thought is that the pump was somehow attached to the balancer pulley off-center. There are two ways this could happen. First, the play in the through holes on the pump allowed the entire assembly to move around relative to the balancer pulley, causing imbalance. Second, the tapped holes on the balancer pulley are slightly off center and the slop in the pump holes are used to align it properly which was not done correctly by the previous owner.

I am leaning toward the first so I put some small spacers around the bolts to eliminate the slop between the bolts at the pump mounting flange holes. The thought is that this will keep the pump aligned properly on pulley.

I haven't tested this yet because I am working on some other boat projects. When I get things tidied up I will test it out. If this doesn't work I will try theory two and see if I need to use the slop in the flange holes to move it into alignment properly.

redlightning
05-08-2010, 05:51 PM
There are spacers between the raw water pump and the balancer.

Craig
05-09-2010, 02:54 PM
We are referring to different things. The spacers that sit flush on the balancer between the balancer and the pump are there.

I am talking about a radial spacer, or a thin ring, that basically makes the through holes in the raw water pump smaller in diameter.

Craig
05-20-2010, 09:49 AM
Update: Wrong pump!

So adding the radial spacer did not help. Actually, I think it made it slightly worse.

This sent me back to the drawing board and after a phone call to skidim, talking with Richard, we realized that the pump the boat is not an LT1 water pump. Rather, it is a Johnson pump for a standard Indmar motor. The only difference is the mounting flange.

It looks like the PO make a mistake and I feel silly for it taking so long for me to consider this as an option. I knew that the LT1 and most other Indmar motors use a Johnson pump but I figured it just would not work at all without the correct one.

I am going to double check the part number on the pump tonight and order a new one.

This is quite a saga, and hopefully it is over.

jacklsl
06-14-2010, 05:31 PM
I have the same wobble on my 99 prostar LT1. Since the water pump shaft runs directly off the center of the large pulley - that I thought was on the crankshaft. Are there spacers on the bolts to help get the pump shaft perfectly aligned to eliminate the wobble?

Craig
06-15-2010, 07:34 AM
There are spacers on my boat, but they do not help with pump alignment. They seem to only push the pump assembly a 1/4" or so toward the bow of the boat. I assume to take care of some clearance issues.

I put a new, proper, pump on my boat and the wobble has disappeared. There is still some movement in the pump that is larger than other items on the boat but it is no where near what it used to be and no longer is a concern to me.