Checking prop shaft for true/ strait

[aook23]

Can I run the engine for a short period of time just to have the engine turn the shaft?

Or is there a better way of checking for true strait.... We hit a rock and rinkled the prop pretty badly im hoping the shaft didnt bend ... what are my chances ... :-?

[RobertJ]

If it is on a trailer I would use a dial indicator and a magnetic base and spin the shaft by hand. I would disconnect the battery and make sure boat is in nuetral so you do start it by spinning the shaft.

[aook23]

I have no prop on the shaft cause its getting repaired and attemped to spin the shaft by hand but it is very difficult to turn ... I'm not sure if its not fully in neatural ... I dont know what to do really ..

[brain_rinse]

What I would do and what I would recommend that you do are two entirely different things... :)

[aook23]

What I would do and what I would recommend that you do are two entirely different things... :)

hahah

well i was just gonna run the boat and throw the dial indicator on it ...

but slight fear of impeller burning up with no water being run thru it ..

other option is wait till I get the prop back on thrus night and go water test .. but I am kinda impateint ...

[brain_rinse]

Do you have a fake-a-lake to hook up so you don't have to worry about the impeller? Without a prop on I think you've removed the biggest safety issue.

[aook23]

No i dont, im not even sure what one looks like or where it connects .. when we bought the boat he showed me a hose I could pull off and fill with the garden hose but I think thats just for keeping the engine cool not supply to the impeller .. ughh leason learnd .. never hit rocks again ..:(

[DOCDRS]

I would not be afraid to run the engine for 5 seconds or even 10. I have with no consequences to the impeller. My experience !! If your real worried pull the hose and spray some silicone lube in the on the impeller before ya do it, but again I wouldn't bother. Now saying that i wouldn't run it for more than 10 without some lube... ya could pull your hose off the vdrive and jam your garden hose in to it then you would have no probs

[drewsky]

Just about Every time I take it out, I run it for about 5 seconds either at my house, or before I go down the ramp, just to make sure everything is going to start fine.

In reality unless you've drained all the water out of your cooling system (I.E. Winterizing) You've still got residual water to keep the blades from seizing up. And 5 seconds is not long enough to get the block warm to require cooling.

Just my 3 cents.

[RobertJ]

I would put the prop nut back on the shaft and use a wrench to slowly turn the shaft while watching the dial indicator. I would also disconnect the battery so you don't hand start the boat.

[aook23]

I would put the prop nut back on the shaft and use a wrench to slowly turn the shaft while watching the dial indicator. I would also disconnect the battery so you don't hand start the boat.

Thats a good idea, im gonna try that tonight

[Waynes345]

A fake-a-lake is good to have on hand regardless. There is also a thread on the board about a home made version. Here is a link to the one I bought:

http://skidim.com/prodinfo.asp?number=FAK01

[aook23]

So heres the deal, I used a Dial Indicator and attached it to the trailer and ran the boat for only 5 seconds and got a reading of .008 and .010 of of movement but considering the trailer was shakin a bit from the boat engine rumble ( which was sweet by the way :cool: ) I am being optimistic and I think that is minimal for the setting and should find out for sure if there is a vibration tomorrow as soon as I water test the boat once I install the new prop ... fingers crossed..

Anyone have any input on what they think based off those readings ..

[drewsky]

Ok, Technical question, Is that Dial indicator in MM or inches?

[DOCDRS]

I found this post very interesting and did some searching. You need to check the propshaft by hand not with the motor running. plus where on the shaft did you check it pre or post strut. I couldn't find a tolerance other than .002 but thats on outboards. Don't have mine here but is there any movement (lat/vert) just by applying some force to the shaft by hand....ie cutlass bearing play? when you put the prop back on and spin it by hand , if it binds more at a particular point then the shaft may be bent...or the alignment could be out ?
If it binds or your gauge shows it out I would unbolt the engine/propshaft coupler and recheck your shaft trueness and engine alignment to determine the cause.

[aook23]

Ok, Technical question, Is that Dial indicator in MM or inches?


It was in inches

[aook23]

DOC,

I cant seem to get the thing to free up at all in "Neautral" Does every one else seem to be able to free spin there prop at the "Neuatral" Postion because it feels like fighting engine compression or something,,,

I checked it pre strut but like I said it was running, which your are sayin is not a accurate reading wich I completly believe.

I get my prop tonight so I guess that will have to be the real test ...

also what should I tourqe the new prop to ?