Slight vibration dp-c1 drive

Hi, I developed a vibration at the end of last season, when I pulled the boat out of the water I removed the props and drive. I inspected the the u-joints and checking by hand they feel great. There wasn't any water in the bellows. When I removed the props the hubs where corroded and off center. I had the hubs replaced and I also replaced the pds bearing and bellows while the drive was off. The majority of the vibration is gone but I still have a noticeable vibration around 1200 rpm, it is most noticeable when coming off plane. I do not see and damage to the props (stainless) but they where not balanced. Again the hubs made a world of difference but it's not 100% imo. I bought this boat (pursuit 2460 Denali) last year and repowered it so I don't have much time on the water with it. Just want to make it right.. any help would be much appreciated! Thanks Brian

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Schoorthing said:

Hi, I developed a vibration at the end of last season, when I pulled the boat out of the water I removed the props and drive.
FYI and FWIW...... unless contimplating doing suspension fork, pivot tube or Intermediate housing work, there is seldom a need to remove the entire stern drive.
For the work scope that you have described, we typically remove the transmission only.

I inspected the the u-joints and checking by hand they feel great.
It is very tuff to determine the condition when feeling by hand.
Compared to the automotive bearing cross, the Marine bearing cross (due to less continuous articulation) is more-so "point loaded".
The point loading will create a more confined wear pattern on the trunion that may cause a vibration.

There wasn't any water in the bellows. When I removed the props the hubs where corroded and off center. I had the hubs replaced and I also replaced the pds bearing and bellows while the drive was off. The majority of the vibration is gone but I still have a noticeable vibration around 1200 rpm, it is most noticeable when coming off plane. I do not see and damage to the props (stainless) but they where not balanced. Again the hubs made a world of difference but it's not 100% imo. I bought this boat (pursuit 2460 Denali) last year and repowered it so I don't have much time on the water with it. Just want to make it right.. any help would be much appreciated!
Suggestions:
Have you checked for AFT prop shaft run-out? (Max .003" allowed)
Are you able to test a "like" and known to be good set of props?
The C-1 lower unit uses the short vertical shaft, of which requires the extended spline coupler. Have you checked this coupler for "twists" or ___?

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RicardoMarine said:

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Thank you for the quick reply. I do not have access to another set of props, I would also like to note that I do have a vibration on full lock turns but it's not that bad. I am coming from a boat with twin inboards so I don't have much experience with I/o. Is some vibration on full lock turns acceptable do to the articulation of the u -joints? I do not know any of the maintenance/repair history of the drive, it has around 800 hrs on it and as far as I know is all original. If you think replacing the u-joints is the least intrusive repair, I will start there. Again thank you -Brian

Also would you happen to have a p/n for the u-joints? Thanks

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Schoorthing said:

Thank you for the quick reply. I do not have access to another set of props,
It would be a good idea if you were to carry a spare set on board.
Once you have them, give them a try and see if they affect the vibration one way or the other!

I would also like to note that I do have a vibration on full lock turns but it's not that bad. I am coming from a boat with twin inboards so I don't have much experience with I/o. Is some vibration on full lock turns acceptable do to the articulation of the u -joint?
The universal shaft will accept "full lock" at low speeds.

I do not know any of the maintenance/repair history of the drive, it has around 800 hrs on it and as far as I know is all original. If you think replacing the u-joints is the least intrusive repair, I will start there.
I don't necessarily subscribe to the "fix or test for the easiest things first" stategy.
If the universal shaft's bearing crosses are suspect, the transmission Bearing Box will need to be removed for the replacement work.

Again thank you -Brian

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Schoorthing said:

Also would you happen to have a p/n for the u-joints?
I think that you mean "bearing crosses"! (what some people call a U-Joint is actually a "Bearing Cross")
Volvo Penta used two styles over the years.
Either style is an automotive adaptation, and are considered industry standard.


Here is an old ME.com thread from 2010 on the same basic topic.

http://www.marineengine.com/boat-fo...m-a-Volvo-3860232-U-joint&p=470648#post470648

In that thread, I posted a list of interchangeable bearing cross part numbers.
(see below)


NOTE: your C drive will NOT use this style!

For the older internally clipped:
SPICER# 5-1306X (my preference)
(I cannot verify the following..... info passed on by another member)
ROCKFORD# K1306
DETROIT# 7260
NEAPCO# 1-6300 / 1-6301
PRECISION (MOOG)# 315G
TRW (FEDERAL MOGUL)# 20030 / 20030P



NOTE: you will most likely have this style.

For the externally clipped:
Neapco (USA) 1-0005 (watch out where the zerk is located)
some will be in the cap, of which we can not use.

Meyle (German) # 3520 997 Art No 514 814 0002
replacement for #1-0005
dual zerks in apex of cross, 180* apposing.
these are of very high quality and are expensive!

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Thanks for your help, I will update with findings when time allows. The cone nut has definitely seen better days, have you ever seen any issues with a worn/ corroded cone nut? The reason I ask is that the prop shop recommended the new hubs be soaked for 1 hr before use, which I did. I took the boat up river about 7 miles with multiple speed changes. The boat ran flawless, no vibration at all!! On the ride back when I powered slowly out of a no wake zone I felt the vibration again for a short period but now it seems to be getting more pronounced but it is at lower rpm only.. Once on plane it runs smooth. The boat is in the water but I will check to make sure that the cone nut is not slowly backing off. Again I am new to I/o's and am trying to learn them so I really appreciate your help.

Thanks for your help, I will update with findings when time allows. The cone nut has definitely seen better days, have you ever seen any issues with a worn/ corroded cone nut? The reason I ask is that the prop shop recommended the new hubs be soaked for 1 hr before use, which I did. I took the boat up river about 7 miles with multiple speed changes. The boat ran flawless, no vibration at all!! On the ride back when I powered slowly out of a no wake zone I felt the vibration again for a short period. now it seems to be getting more pronounced but it is at lower rpm only.. Once on plane it runs smooth. The boat is in the water but I will check to make sure that the cone nut is not slowly backing off. Again I am new to I/o's and am trying to learn them so I really appreciate your help.

What you are calling a cone nut is actually a "spinner".
Spinners rarely loosen up if they are secure and if the center locking bolt is snug.


Make certain that you are using the small spacer rings in front of each propeller!
DO NOT EVER Forget to install these spacer rings!



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The only spacers I have are the are the 2 thrust washers, the plastic washer on the spinner was missing so I got one and installed that as well. Am I missing additional hardware that may have been left out by previous owner? 3858457 front, 3858458 rear and 854294 for spinner.