Second trip out... bad vibrations? 18202 Evinrude

Well... I took the boat out today.

Something is still not right...(I need to do a link & synch) but I can handle that.

What really worries me is I'm getting vibration from the lower unit - I think its the lower unit. Its fine at no wake speed, any faster and it starts vibrating, I don't mean it shaking like it going to shake the boat apart but you can certainly feel it. At higher speed I couldn't tell if it was vibrating or not.

Other than a bent drive shaft, what do I need to look at? I'm going out to drop the lower now.

Re: Second trip out... bad vibrations? 18202 Evinrude

prop..prop shaft

Re: Second trip out... bad vibrations? 18202 Evinrude

I just replaced the prop drive pin last trip out; let me go pull the prop off... and see what I find.

Re: Second trip out... bad vibrations? 18202 Evinrude

So are there any other possibilities or is it pretty much the driveshaft, propshaft or prop ? (or possibly all 3)

Everything appears as it should with the prop... I may be able to take the driveshaft to work and get someone to check it out there... any suggestions on how to get the impeller drive pin out? (Its stuck)

How do you check if the prop is bent? Can my Evinrude dealer check it out?

Re: Second trip out... bad vibrations? 18202 Evinrude

is it too tight to pull out with pliers?...with the prop on and gearcase in neutral, can you see any wobbling of the prop as you spin it?...any side to side, up or down movement if you grip the prop and try to induce movement in the shaft? if so, you're gonna have to take the gearcase apart and see what's going on..if not, a prop shop or maybe the dealer can check the prop for you

Re: Second trip out... bad vibrations? 18202 Evinrude

I cannot get the impeller pin out... its really in there! I do not want to use heat.

I don't see any wobbling in the prop nor can I get the prop shaft to move. (I'm really thinking it may be the driveshaft but I'm going to check both shafts.)

A buddy at work has a dial indicator, if I can get my hands on it what is the max it can be off.... how many thousandths is the tolerance or is there no tolerance?

Re: Second trip out... bad vibrations? 18202 Evinrude

how much movement do you have in the lower shocks to exhaust housing mounts?..upper mounts?...any flywheel play when lifting up on it or trying to move it side to side?...I don't know the propshaft or d/s tolerances, but they won't be much...also...any chance the engine is running on 1 cylinder intermittently?

Re: Second trip out... bad vibrations? 18202 Evinrude

Remove your prop, put it on muffs, start it up at idle speed, put the lower unit in forward, put your finger on the smooth part of the propshaft. You'll feel if the shaft is bent.

Re: Second trip out... bad vibrations? 18202 Evinrude

AITn -

I'll have to go check the mounts, I know there is some shaking in the motor mounts... I'll check the flywheel too, but it was solid 2 weeks or so ago when I pulled it to re-check the points gap. She starts on the first pull when warm, 3 pulls when cold now.)

I checked to see if it was running on one cylinder and got a nice zap (or two) in the process. I'm not real sure how I could check to see if a coil is dropping spark when running.

Thanks for the help, hopefully I can check this out and post back tomorrow.

mike_b - good idea, but you can't run these older motors on muffs...if I had a flushette I suppose I could run it off a hose.

I'm eyeballing a used lower unit now with a driveshaft... hopefullly I can get it fairly cheap.

Re: Second trip out... bad vibrations? 18202 Evinrude

Have you tried a different prop? The two biggest causes of a lower unit vibration are a bent prop shaft and or a damaged prop.

Re: Second trip out... bad vibrations? 18202 Evinrude

how tight did you torque the f/w?...if this vibration occured shortly after this work, I'd go back and reexamine it...seems unlikely you'd bend/warp either the d/s or propshaft with w/o hitting something..how tight is the prop nut on?..can you pull on the prop and feel any play between it and the nut?

Re: Second trip out... bad vibrations? 18202 Evinrude

I bought this well over a year ago, took me a while to get it taken apart (saltwater motor that was not well cared for and sat in a barn for "a few years"). I replaced, inspected, and repaired all of the usual things for a motor that has sat around for a few years unused. (It took me a few months just to get the driveshaft out and get the rusted/ corroded shift rod connector bolts out of it. I will NEVER forget to install an o-ring on any of my driveshafts.)

Took it out for a first run and worked my way up to WOT, it slipped. It ran pretty ragged the whole time... (Turns out the prop drive pin was broken. I found rusty bits of 16 penny nails behind the prop as well as an old piece of bolt which was used in place of the proper pin... which worries me.) Replaced drive pin... pulled flywheel again...reset points...found I had TWO seals in the drain plug - which was the source of the water intrusion in the lower... a week or 2 later I decide to go out to try it again and here I am.

I should have a very nice dial indicator to use tomorrow to check the driveshaft and prop shaft. (thank you Fred!) I have not tried another prop yet. (The lower I was looking at is unlikely to come my way.) I still need to recheck and maybe synch the carb and magneto...

The flywheel was torqued to 42 ft lbs (spec is 40-45 lbs)

Re: Second trip out... bad vibrations? 18202 Evinrude

I do not have the best workspace to try to take precision measurements... but from what I can tell neither shaft is true.

The areas I checked were, at the worst, .004" off.

I am not 100% confident with those readings.