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Storm861triple
08-04-2008, 12:02 AM
I've posted numerous times about doing a super quick check of your drive train, by spinning the prop to see how much drag there is.

I was out today in my friends '00 190 which I did a complete alignment on a couple years ago. Prior to this work, this boat was a typical DD inboard, "two fister". Anyway, I had my camera, and thought I'd take a quick vid to post on here to show what I'm talking about. I've always said that a perfectly aligned drive train (including the strut) will spin by hand w/virtually no effort. Here is what I'm talking about:
http://www.youtube.com/watch?v=wTQaetaYQls

The thing turns as easily as my old boat's (outboard engine) prop did!

This test doesn't completely guarantee that the drive train is perfectly aligned; it is possible for there to be a slight engine-propshaft angular misalignment and still have a pretty easy to turn prop, But one thing is FOR SURE: if you need "two fists" to turn your prop, then something is out 'o whack.

bigmac
08-04-2008, 07:45 AM
Nice demo, but to spin that easily makes me wonder whether or not the strut bushing is excessively worn...

I've always thought that that was the source of most driveline drag, and by design.

Storm861triple
08-04-2008, 10:34 AM
...the strut bushing is excessively worn...I've always thought that that was the source of most driveline drag, and by design.

No. On a stock, properly aligned drive train MOST of the friction comes from the packing. Then the Cutlass bushings after that, though if everythign is STRIAGHT, it shouldn't be much at all, as shown in the vid.

In this case, the strut bushings were both replaced when full alignment was done. They have about 50 hours on them at this point.

MY boat is about the same, and I did strut, bushings, shaft, PSS, Prop balance, and my FULL alignment all at the same time, several years ago.

Roonie's
08-04-2008, 10:42 AM
Mine spins with one hand but it won't spin freely if given a tug on like the video. It has noticeable resistance to it but I still can spin it with a finger. Once I stop spinning it, it will stop as well (unlike the video). Mine has never hit anything and only has 46 hours on it from new.

Hrkdrivr
08-04-2008, 11:11 AM
Does that rudder have some sort of horizontal piece attached to it on the bottom (like an air chair foil) or is it the prop guard on the trailer I'm seeing?

My V-drive turns w/one hand, but not quite as loose as that...

BrianM
08-04-2008, 12:46 PM
Does that rudder have some sort of horizontal piece attached to it on the bottom (like an air chair foil) or is it the prop guard on the trailer I'm seeing?


That is the T- Rudder that they put on the 98-00 190s. Part of the Positive Pressure Tracking system

Storm861triple
08-04-2008, 02:02 PM
That is the T- Rudder that they put on the 98-00 190s. Part of the Positive Pressure Tracking system

This is getting off topic, but what he^ said. I don't like that thing. I don't know what "problem" it must be trying to cure, but one time I put a hand finished SS three blade prop on that boat, and in the water, it vibrated CRAZILY! It was terrible; so bad it felt like something might break. We pulled the boat, started it in the lot, and brought it up to 4k RPM for a second, in gear....NO vibration....meaning it wasn't the prop -whcih I knew anyway. I think it had to do w/the dynamics of the propwash going over that horizontal thingy-ma-bobber.

Back to the vid; I'd say that boat is BEST case. It's got the alignment, and a PSS seal. If you can turn w/one finger, it's pretty likely, IMO that things are good for your boat.

CantRepeat
08-04-2008, 05:17 PM
I just replaced my prop, shaft, strut and rudder housing from a unplanned "landing" damn low waters.

But with new bushings mine turns that easy as well. It might not have if I would not have gotten some really good information from the kind uses here.