Knocking

[kmkramer71]

Here is the deal. My boat went to the shop due to running a ground. They had to pull the motor to get to the glass repair. When they put it all back together there is a knocking. I have not heard the knock first hand. There are no codes on the scanner. New shaft, rudder and strut along with impeller,belt and fluid change since the motor was out. They now have the vdrive and transmission apart and still cannot find the noise. It is just when under load. Idle purs.

If anyone has any suggestions please comment. I plan to go to the shop Tuesday. Marine power has been assisting also.

[chpthril]

Sounds like a damaged dampener plate

[kmkramer71]

Where is it, what does it do and how could it get damaged when you run a ground? I was going about 5 mph.

If I ask them on Tuesday if they have thought about tat part I should know what it does. Btw, 05 22v

[chpthril]

its between the engine and transmission. prop, shaft, V-drive and trans stop rotation, engine doesnt.

Did they forget to refill the oil after draining it and then ran it? Its hard to armchair technician a knock. The frequency and tone are invaluable for isolating. also, narrowing down where its coming from. Could be something that fell down the throttle body and is now on top of a piston.

[kmkramer71]

I'm sure they refilled the oil. They have gone through their check list several times and seem confident that it is not in the engine. At idle there is no noise at all and the engine sounds perfect. Then they put it in gear to about 2k and the noise starts. This seems counter to what I googled about a damper plate being bad. I'm no mechanic!

I emailed them to ask if they considered it. I hope they inspected it since they have removed the transmission twice now and currently have the v-drive apart now. I assume the damper plate is visible when you remove the transmission from the motor.

[kmkramer71]

update, I asked them about the damper plate and they have looked at it and it looks good. They now have the drive gear disconnected and it appears to be ignition timing is the culprit. They are constantly sending ECM output to Marine Power for diagnostics.

[kmkramer71]

The engine has been pulled again. timing chain looks. still trying to hunt it down.

[Wakeman22]

Like chp said its hard to diagnose a noise proplem without being there. I have heard low end knocks that come up under load and went away when not. My expenince turned out to be crank endplay. Should not be the problem with yours. But then again they are heading to the front top and lower end.

Will be interesting to know what it turns out to be. Keep us informed.

[kmkramer71]

A new ECM from Marine Power has fixed the knocking. The entire engine was mostly eliminated. Does anyone know if the ECM could be damaged from running aground? That is the real question now ;

[kmkramer71]

actually was not the ECM, it turns out the ACME 537 prop was causing the issue. Replacing with a ACME 515 proves to make my boat act perfectly.

[IDBoating]

At idle there is no noise at all and the engine sounds perfect. Then they put it in gear to about 2k and the noise starts.

Glad to hear you've got it resolved, but a you'd think a prop problem would have revealed itself pretty quickly. For example, if the noise is there at ~2000 RPM did they ever rev it up with the transmission disengaged (i.e. pushing the little button on the throttle lever)? If it was indeed a prop issue that would have eliminated the sound, pointing you away from the engine and farther down the drivetrain. No questions about oil refills, ECM's, etc.

Anyway, glad it's fixed!

[kmkramer71]

they kept saying the noise was there with and without load. i don't know what to believe anymore. 2 months without the boat. I'll drive it today.

[chpthril]

actually was not the ECM, it turns out the ACME 537 prop was causing the issue. Replacing with a ACME 515 proves to make my boat act perfectly.

Sounds like your boat has the black 1:1 gear drive. If so, then the 4 blade 537 would not be the right prop and a 3 blade like the 515 would. I hope this does indeed fix it.

[IDBoating]

they kept saying the noise was there with and without load.

Load isn't the same as not engaging the transmission. Out of the water, there's almost no load on the engine when you rev it up even with the prop turning. (This is also why it's hard to diagnose fuel delivery problems on the trailer - even at relatively high RPM's you're burning very little fuel because the engine isn't having to work very hard.)

Oh well. It would have been nice to know the results of this test, but if it's fixed on you're on the water today, that's what matters!

[kmkramer71]

boat runs well. I feel there is more vibration than before. What other prop might I try? Again, they misplaced my damaged one so I'm not sure what 3 blade was on there previously. Just happy to have her back at this point.