No Power and no RPMs

[keelcooler]

Another a4 returned to service with a couple of gaskets and elbow grease. The logic and simplicity of this motor does inspire confidence.

[Baltimore Sailor]

She may not have slipped out of gear at 2000 rpm. Rather, the prop may have cavitated on you, which sounds the same. Props want smooth water flow over them, and if you jump the rpms too quickly they'll start to cavitate, and then you're essentially spinning the prop in air.

If you're getting a good thunk going into the detent, you're probably OK. Try revving her up more slowly, or taking her off the lines and out into real water and see if it still "slips." If it does then, I'd say you're justified tightening the collar one notch.

[sastanley]

yahoo!

Nice work, Rob.

i agree with BS....before you adjust it, take her for a spin. At 2,000 RPM she'll be making a wake so big the marine police will ticket you for speeding, so you won't need that much RPM under normal use.

The point is, run her under not-at-the-dock conditions before adjusting stuff

Man, you work fast...I've had my boat almost 18 months and I am just getting around to try to adjust my valves tomorrow..I'll take my valve tool & the magnet just in case I screw it up

Awesome!

[Baltimore Sailor]

I just took my boat out for her shakedown cruise after my tranny and carb adjustments of the spring. She'd checked out OK at the dock, but it's a world of difference to have her out on the water.

I pulled out of my slip -- only hindered by forgetting to let off the starboard bow line, but which allowed me to test my new neutral zone by quickly downshifting to run forward and drop the line, with none of the wandering as before, caused by the small neutral zone.

Took her out into the bigger water and tested the new reverse settings -- worked fine, backed up with no more prop walk than before. Then I took her out toward the Patapsco River at 2000 rpm with no problems. Because of time restraints I turned her around before the last day mark and headed home. I was able to approach my slip in forward at 600 rpm, which is amazing compared to how I inherited the engine.

She backed into her slip the same as always, only with better control: when I put her into neutral this time she actually WENT into neutral, instead of some uneasily negotiated zone between forward and reverse.

Very sweet. Can't wait to take her out for real after I get my mainsail back from the loft.

[RobH2]

Hi guys. Thanks for the comments and congrats.

Yea, I did go out on the water today after I made sure that all my repairs were sound and I wouldn't konk out. Cooling is fine, idiling is fantastic and everything is purring.

Whatever the cause, the symptom I'm having is it feels like the drive train just lets go at about 2000 RPM now and again. Now I didn't go look at the shaft to see if it was still spinning as the engine compartment was all buttened up. I guess it could be cavitation. I don't know how that feels except for when my Honda 9.9 prop would rise to the surface in big rollers.

Let me ask you, once the prop cavitates and is delamnated from the water will it fill in on it's own ever...because it sounds like you are in neutral all of a sudden and the engine just revs up? Of course I immediately pull the throttle back but is that what cavitation feels like? I turned the clutch up one more notch but getting it into gear felt like I was breaking the shift lever so put it back. I'm sure the thing to do is to throttle back and let the prop gain lamination.

I guess a good way to tell is next time it happens is to leave her in gear, throttle back, let the prop set again and then slowly throttle back up. Or does that tell you anything? I also don't know exactly what a clutch slip feels like not ever having had a clutch before.

I am getting a low frequency vibration that is a bit worse when at lower RPMs. It is never gone completely. Is that a symptom related to the issue above or something completely new to diagnose?

Rob

[Baltimore Sailor]

In my experience, once the prop cavitates it will not recover without throttling down.

I had the exact same experience as yours, running at the dock, straining against the lines: I pushed the throttle up quickly to 2000 rpm and it "ran away," sounding like it had slipped out of gear. I throttled back down, then eased it up to 2000 rpm again and it never "slipped" again. When I took her out today I got up in that rpm range with nary a problem.

As for your low frequency vibration -- I had the same thing today in my boom, which is barren, my mainsail being in the shop. It never did that before. My alcohol range also "buzzes" at certain idle levels -- it's just something an engine will do to your boat. Everything's got a harmonic frequency, and if your engine hits it your boat will respond. There's not a thing you can do about it except damp the vibration where it occurs, if it really bothers you.

[RobH2]

Thanks for the detailed info on how cavitation feels and acts. I'll figure that out.

The vibration doesn't bother me. I'm just getting used to a new 'to me' boat and it's idiosyncrasies and noises. I'll soon figure out what's normal and what merits investigation, tweaking or repairing. My Columbia 8.3 with he Honda 9.9outboard had it's noises and harmonics with the boat too. If one of you had said, "yes, that vibration is a clear indication of xxx" then I'd be looking at how to fix that. Now I'll just start to get used to my boat and figure out her temperament and voice...

So I guess this is the end of this thread. I've repaired the "No Power and no RPM's." Hopefully it will help someone else rebuild their top end and diagnose blown gaskets. I thank everyone for the help. It's a pleasure to be part of this community. You are all so attentive and active here and your expertise is invaluable. Thanks again and see you on the water...

Best regards...Rob and Magenpie...