Nasty vibration at idle on port side of 2017 AR210

[motomark73]

Yesterday while under heavier load than normal (Labor day friends and a boat full of gear) I am fairly confident one of the port side jet pump bearings is going. I did not notice it at all until I docked. Even at wake speed it goes away- at idle it is a very nasty vibration. I spent 3 hours last night trying to pull the jet housing with no luck. It is 5 bolts- no magic in this and I'm reasonably mechanically inclined. The service manual trick of pulling the rear ride plate and splitting it with a flathead screwdriver did not work. I tried a slide hammer to no avail. The splines seem to be seized/corroded in the intermediate bearing in a major way. I have had the boat just this season but it was a Florida boat and I know it saw salt water. Overnight I removed 2 of the nozzle housing bolts and ran some steel cable to a come-along to a nearby tree to put some tension on the entire jet pump assembly. This morning I used a piece of wood to tap on the shaft through the bottom intake grate close to the spline, still with a ton of tension on the pump assembly (found that idea on GreenHulk)- but even that did not work. I really do not want to have to try putting heat on the shaft, but one of the allures of this boat was the ease of working on it; not so much right now.

1. Open to any other suggestion on how to get the splines to release from the intermediate bearing...at this point I'm wondering if previous owner use permanent loctite? Appreciate any feedback/ideas that may have worked for others.
2. We have about 6 weeks of season still here in Georgia- since it runs OK above idle would you keep running it? On the hose it is was easier to isolate where the noise was coming from and it's definitely one of the bearings in the jet pump- would you run it as-is or will it seize up and take other parts of the drivetrain with it?

 

[Cobra Jet Steering LLC]

Hard to say but there are pry locations between the pump sections, first you can remove the cone and look at the grease for trash or water in the pump just to determine if it is the pump.
It may be the intermediate bearing housing or who knows I had a bad motor mount once that was doing things like that but the pump usually gets worse as you go fast , are you sure there is not an object hiding in the impeller or around the drive shaft. Or a bad spark plug causing it to run bad at idle usually the faster you go the worse it gets if it is a pump. I made a special slide hammer to get the pumps out when I do those .

 

[motomark73]

Thanks for the feedback, I could find nothing in the impeller housing either from the rear of the boat after I removed the nozzle or down from the cleanout port, but I do agree that makes more sense and I will have to check it one more time- maybe something really small that managed to get itself caught "just right". Interesting feedback that if it was a bearing it would like get worse with higher RPM, so now I'm questioning what I heard, but I can pull the cone off easily enough and confirm. Fairly certain it is not a plug, I had a warm start issue on the starboard motor and changed all the plugs in both motors about 10 hours ago.

 

[Cobra Jet Steering LLC]

ok just remember to clean the O-ring on the cone and put some silicon gasket compound on it when you return the cone to the pump,, adding in some gear lube is also a good idea. do a search on that subject also. As for trash in the impellor may times you can not see it from under the pump .

 

[motomark73]

Update, finally got the port side jet pump out. I think I found the source of the vibration (see photos).I think it jammed pretty bad when it broke. The spline section is still inside the intermediate bearing section and it's proving difficult to remove. Ran it on a hose and it think the intermediate bearing is good, but looks like I may be forced to move motor forward to pull the intermediate assembly to get the broken spline out. Absolutely nothing showing in the pump and impellers are clean. A few hot spots in the impeller housing, appears to be the swelling issue. Does it make sense that a too tight tolerance would break the drive shaft or do I potentially have an incorrectly shimmed engine causing an alignment issue that contributed to failure?

 

[David Martin]

Ouch!!!!!

 

[Cobra Jet Steering LLC]

check and compare the space between the 2 parts at the back of the engine see if the one that failed is wider than the good one meaning you need to reposition the tube in the intermediate bearing that the driveshaft goes in. This tube is set in place using a press. not sure what the correct spacing between the 2 halves is supposed to be, with the intermediate bearing out of the boat you may be able to weld the broken part out by welding a large bolt to it and work the piece out or you will need to replace that part. this picture is the power take off on the engine and the coupler to the drive shaft the space between the parts is suspiciously wide and this picture came from @Tobes who is working on an intermediate bearing issue. he too would probably like to know the exact correct space between the 2 parts.

 

[motomark73]

Jeff, you are a true resource to the board, thanks for all the feedback. I'll post back as I get details.

 

[motomark73]

I had basically conceded I was going to have to pull the motor to pull the intermediate bearing. Last ditch effort was to drill a hole in the piece of the shaft that was in the bearing housing, whipped up some JB Weld and drive a brass screw in as far as I could with a piece of wire on the end. It worked!!! Got to love some JB Weld.

 

[1969mach1]

I had basically conceded I was going to have to pull the motor to pull the intermediate bearing. Last ditch effort was to drill a hole in the piece of the shaft that was in the bearing housing, whipped up some JB Weld and drive a brass screw in as far as I could with a piece of wire on the end. It worked!!! Got to love some JB Weld.

BRILLIANT!

Is it me or does that look like a bad casting on the spindle?

 

[Cobra Jet Steering LLC]

The picture bothers me, something allowed that drive shaft to wear down at the end of the intermediate bearing tube I would strongly recommend you inspect the splines inside it and any play in it the driveshaft is supposed to be tight in there . if it is worn it will probably repeat the same process so check it closely.

 

[motomark73]

I rebuilt the jet pump on the port side with new WSM shaft. I put the shaft in my deep freezer for 24 hours and hit bearings with a heat gun on low. Went together with surprising ease. I made a slurry of Lucas marine grease and Lucas synthetic gear oil and put that in both jet pumps. Was able to get both the SBT housings with Delrin inserts. Also completely resealed both tunnels. I ran the port motor on the hose and everything was smooth and sounded identical between port and starboard with no jet pumps. No issues with port driveshaft fitting properly, no play of any kind. I believe I had a driveshaft that was less than ideal and also swollen pump housing put additional stress on it causing the failure. I wanted to swap impellers but there are no OEM ones anywhere. They were in decent shape, but definitely some signs of very minor cavitation on both. Best speed I ever had earlier this season was 36 mph GPS and that was only in perfect conditions with less than 1/2 a tank of fuel. I showed 41 mph GPS last night which is a huge improvement and close enough to new spec that I am very pleased. Maybe new impellers would get me to 43. Both motors held 7900 rpm, which was not the case previously. Thanks very much to all!