Cutlass bearing replacement

There could be synchro or engine problems but first you need to figure out whats wrong then worry about the fix. Have you tried running without the sync???
 
I like to understand both root causes and resolution when making informed decisions on what I should do - that's why I ask questions. IF the fix is relatively simple, and inexpensive to apply then I would just knock it out, eliminating them as potential causes. You can see I've spent plenty of time and money chasing everything else at this point!!!! If the fix is expensive, I can learn to live with a little vibration at this point.

I have described above what I experienced when playing with the engine sync either way - does not seem to eliminate vibration while keeping me in a comfortable position to keep the power balanced while running. Again, it seems to follow port RPMs more...

What potential "engine problems" are you referring to that might be associated with this? We can ignore tuneups & typical associated components (they're all new).
 
gas or diesel? in either case uneven fuel flow would be one suspect.
 
are you saying that it happens with synch off?? What about if you purposly offset rpms??
 
I forget, did you examine the cutless bearings?
 
Hi Bruce
answers to your questions:
1. Gassers - could a carb rebuild be a contributing fix? (I haven't done that yet, and 1 is "old")
2. See Feb 11th post on purposely offsetting throttles
3. I have not yet re-tested the port side forward strut bearing that I suspected I felt a little play in last year. Since this tends to follow the PORT throttle more, I am gravitating toward understanding more about this bearing.
Don
 
Don,
When you had your props conditioned did you use a facility that uses Prop Scan? You may still have an issue with your wheels. The reason I say this is, I just dropped my 28 x 34 wheels off last Thursday for service. They were put on the prop scan machine to determine the issues at hand. The starboard wheel that hit a chunk of wood last year at less than 5 miles/hour was in better shape than the port wheel that did not hit anything. The starboard had only a few minor dings. The port wheel was out of pitch and only utilizing 2 of the three blades. Also the cuppings were all off. Now for the kicker, The place I sent my wheels to last year due to damamge that occurred during transportation and delivery of my boat reapired the wheels, however they do not use prop scan. They looked ok but I noticed I was 20-30rpm off on my port side. So that will be the last time I use them.

You may have an issue with your wheels that are still causing a vibration. If you have a local prop scan repair shop in your area, it may be worth it to have them scanned. They usually do not charge for a free scan. When using Prop Scan a chart will be printed that shows what your wheels were before they were fixed and after they were fixed.
 
so you never tried it with synch disabled?
 
I see you are in MI. I suggest scanning the props, checking the cutless bearings then run the synch tests and IR tach tests after you launch. Until then there isn’t much to be learned.
 
Bob
Interesting you bring that up. I was wondering myself if the "wheels" are properly tuned, and will inquire with my service shop about propscan use at the supplier they used.

Is there any advantage to dropping the shafts and having the shaft and props "tuned" together (I know this was NOT done)? Seems I remember reading something in B-ed about someone eluding to that a couple years back...

Bruce
I must be missing the "synch" you are referring to. I was referring the the synch gage I have on the instrument panel. It only indicates if the engines are synchronized, and does not influence any input to the engines (only input is to the captain). Given the reference you made to "disabling synch" there must be something more complicated or mechanical that you are driving me to recognize. Sorry if I missed this earlier...
 
UPDATE:
Wheels are being removed. Propscan has an outfit (near Kenny I think, in Huron OH) that have responded very positively. I don't mind the drive provided this does the trick. Will update you on what they find. Of course, the real test will be when she splashes.
Don
 
update:
Had service technician examine all cutless bearings. Verdict = they are fine. Propscan next...
Kenny - any feedback (+/-) from prior clients on that place near you? It's a bit of a drive for me (due to the Wolverine Propshop near Detroit now being closed).
Don
 
Yes I thought that you had an auto synchronizer.
 
Update: PropScan was performed today. BOB is the winner on this call. One of the wheels the service department had rebuilt does not even meet Class 3 specs. I am going to have them tune me up to CLass 1 standards and see what happens.

Here's a question I could not answer today... Should I go with the original pitch and risk the engines working harder than needed (his concern), or compensate some to a 20 pitch for a WOT rating = 4200 (engines have 1200 hours)? PropScan was interested in my WOT rpms to fine tune the pitch needed. The boat is rated for 4000-4400 WOT and came with 22 pitch, flat, 4 blades. I advised him I don't ever remember seeing my tachs above 3800 WOT (his computer estimated I would need 18 pitch for 3800 WOT range on my boat). One also has to take into account tach error on old gages, and the engines are getting on in years.
Any one been in a similar siutation before and have some good advice?
Don
 
Update: PropScan was performed today. BOB is the winner on this call. One of the wheels the service department had rebuilt does not even meet Class 3 specs. I am going to have them tune me up to CLass 1 standards and see what happens.

Here's a question I could not answer today... Should I go with the original pitch and risk the engines working harder than needed (his concern), or compensate some to a 20 pitch for a WOT rating = 4200 (engines have 1200 hours)? PropScan was interested in my WOT rpms to fine tune the pitch needed. The boat is rated for 4000-4400 WOT and came with 22 pitch, flat, 4 blades. I advised him I don't ever remember seeing my tachs above 3800 WOT (his computer estimated I would need 18 pitch for 3800 WOT range on my boat). One also has to take into account tach error on old gages, and the engines are getting on in years.
Any one been in a similar siutation before and have some good advice?
Don
 
Don,

Glad to hear your making some headway on this issue.

I would have the wheel tuned to reach your WOT. The reason for this is that you can cause damage to the engines if they do not meet the recommended RPM as stated by the manufacter. It is better not to stress the engines if the wheels are under propped than over propped. I'd rather be able to reach my RPM's than not reach them.

Provide the prop scan service the following.

Type of boat, model, Express/Sedan/Convertable
Length of the boat and beam.
Weight of boat with normal fuel/
Personal Effects/number of people usually on board
Engine size and horspower
Type of Trans/Straight or Vdrive and gear ratio
Degree of hull

All these item will help determine what the best pitch and cup that is needed to get you to the correct RPM.

Below is an example of what I used a few years ago when Atlantis repaired my props on my 34 Carver with 4 blades.

http://www.atlantispropeller.com/sizing.html
 
Bob - this was one of those situations where I hoped the wheels scanned ok (less expense), but also relieved they did not (root cause resolution).

Good advice on the tuning Bob! I was leaning this way too... but scared I could make the wrong decision for the right intentions.
thx for boosting my confidence in an area where I am not an expert!!!!
I'll let you guys know how this turns out in a couple months (after splashing + some time on the water).
Don
 
When re-installing the wheels, is there something I should put on the shafts to make removal easier (if there should be a next time)?
Don
 
You can use a marine grade bearing grease. I used the lubimatic marine bearing grease. It will not break down in the water. Simply coat the shaft and the inside of the wheels.
 
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