Damper Plate?

[SkiMatt]

Anyone out there have problems with a damper plate or know what one is? I was told I might need to replace mine due to vibration and I'm not mechanically inclined. Thanks

[jthooker]

SkiMatt,

The dampener plate is attached to the crankshaft of the engine and the transmission is attached to the dampener plate. It does three different things: 1) It transfers the rotation of the engine to the transmission. 2) It provides a gear for the starter motor to engage. 3) It provides some of the balance needed for the crankshaft.

The dampener plate looks like a flywheel with springs around the circumference and is hidden inside the rounded (bell) housing on the back of your engine. Several things could cause it to be out of balance and cause vibration: 1) One or more of the springs could be broken and have pieces missing. This could happen due to age, or rust and corrosion, or repeated hard shifts into gear. 2) Some of the teeth that the starter motor engages could be broken off. This is not likely unless you have problems starting the engine occasionally. 3) One of the balance weights could have broken off. This is the least likely of the three things to occur.

If you hear a rattling noise at idle or a clank when you put the boat in gear then the problem is likely due to broken springs. Find a good troubleshooting mechanic (not just a parts-putter-oner) and have her remove the starter and inspect the dampener plate. It needs to be done with a lighted scope or a mirror. It won’t be a conclusive examination but if one of the things mentioned above is found, then that is the likely source of your vibration.
If everything looks okay, it could still possibly be the dampener plate, but there are other external things to check before you spend the time and money to have the bell housing and transmission removed to get a closer look at the dampener plate. Such things could include a bad or loose spark plug wire, a bad spark plug, a loose engine mount, a badly worn belt, or a loose vibration dampener on the front of the engine. Also don’t overlook the obvious things like a bent propeller blade or a bent propeller shaft. Best of luck to you in tracking down the problem.

[Andrew]

u should also check engine alignment. a couple thousanths off can cause a lot of vibration

[richard]

when should change damper

would like to hear about the life and how to consider a damper should be change or not, since I just take out the demper of my GT-40 due to check vibration , the damper looks good,all spring is in position and not broken,it used 500hr,looks not serious rust. should change it as a regular maintaince?

[M3Fan]

SkiMatt,

The dampener plate is attached to the crankshaft of the engine and the transmission is attached to the dampener plate. It does three different things: 1) It transfers the rotation of the engine to the transmission. 2) It provides a gear for the starter motor to engage. 3) It provides some of the balance needed for the crankshaft.

The dampener plate looks like a flywheel with springs around the circumference and is hidden inside the rounded (bell) housing on the back of your engine. Several things could cause it to be out of balance and cause vibration: 1) One or more of the springs could be broken and have pieces missing. This could happen due to age, or rust and corrosion, or repeated hard shifts into gear. 2) Some of the teeth that the starter motor engages could be broken off. This is not likely unless you have problems starting the engine occasionally. 3) One of the balance weights could have broken off. This is the least likely of the three things to occur.

If you hear a rattling noise at idle or a clank when you put the boat in gear then the problem is likely due to broken springs. Find a good troubleshooting mechanic (not just a parts-putter-oner) and have her remove the starter and inspect the dampener plate. It needs to be done with a lighted scope or a mirror. It won’t be a conclusive examination but if one of the things mentioned above is found, then that is the likely source of your vibration.
If everything looks okay, it could still possibly be the dampener plate, but there are other external things to check before you spend the time and money to have the bell housing and transmission removed to get a closer look at the dampener plate. Such things could include a bad or loose spark plug wire, a bad spark plug, a loose engine mount, a badly worn belt, or a loose vibration dampener on the front of the engine. Also don’t overlook the obvious things like a bent propeller blade or a bent propeller shaft. Best of luck to you in tracking down the problem.

The damper plate and the flywheel are two separate parts. The damper plate just bolts onto the flywheel, not the crank. Generally as it loosens up over time you may get a rattle at idle with the boat NOT in gear. When it goes (breaks), it goes big time. I changed mine in the 90 last spring at around 1050 hours. The old one was still fine- turns out the rattle was something else. As for whether you have to change it in your case, I'd have to know more about your boat's symptoms.

[steelerguy]

We Changed ours 3 seasons back in my old boat. 85 ski supreme.

Ski dim had the part for a little more than $100.00

Changed it out about 3 hours and that included MAKING SURE OF THE ALIGNMENT!!!

We heard some funny sounds just as you put it in gear and Changed it the next weekend.

I had my Father in law help us, ( certified Machanic) and wouldnt have attempted it without him and his tools / shop.

[jthooker]

M3Fan,
Thanks for the clarification on the dampener plate/flywheel.
They are indeed two seperate parts.

[SkiMatt]

Great info. Thanks to all of you. I had a very hard impact (unmarked rock outcropping at Folsom Lake) last fall and have recently had a lot of work done to the boat. I was told during the lake test there was a vibration and the mechanic believes it is coming from the dampener plate. The prop, the shaft, the fins, the rudder are all new. Since the shop knows what happened to the boat I would hope they checked the motor mounts and engine alignment too.

Prior to this situation I had never heard of a dampener plate and wasn't quite sure what it did until I recieved all of your posts.

Thanks again.