M25 motor mounts

[KWKloeber]

ron,


I take you comment that the new mounts made a HUGE difference.   Did you replace al 4 old mounts with K75 mounts?

Ed, K75s all around is what you need,  I have several customers w/ M-25s and XPs that are very happy with them.  You don't want to mix K75s and K50s, just take that at face value.

kk

[Mike and Joanne Stimmler]

I put K50's on mine and was very happy and I think that Ron put a combination of K50's and K75's on his and has been happy with those too. I think either will work OK. Maybe Ron or Stu will have a good reason for one or the other but I think that the K-75's are just a little stiffer than the K-50's

Mike

[Ron Hill]

Ed :
"I disconnected the drive shaft and only lifted the front of the engine up high enough to remove the mounts and replace them."  Then I lifted the rear of the engine and replaced the rear mounts

Did you lift the rear of the engine to replace the rear mounts? 
Yes, but I believe that you need to disconnect the riser into the muffler to allow the engine to raise up.  I was also changing out the muffler at that time.  The riser stayed in place - attached to the engine!!

"With the old mounts removed I "wiped" some epoxy on the walls of the lag-bolt holes and install new lag-bolts."

Did you let the epoxy cure before you installed new longer lag bolts?
Yes , I let the epoxy cure.

I take you comment that the new mounts made a HUGE difference.   Did you replace al 4 old mounts with K75 mounts? 
Originally I replaced all 4 mounts with K50s based on Vetus's recommendation.  I found out that the rear K50s were "too" soft and allowed the engine to vibrate and the shaft touch/vibrate against the tube thru the hull at idle.  So later I change out the rear mounts to K75 and all was well.
The difference was unbelievable. 
More than once when I told marina personnel to cast off the bow lines for me - they would come back with "aren't you going to start your engine?  It was already running!! 

a few thoughts

[Ekutney]

Ron,

I plan to remove the riser, it is original.  The mechanic can fabricate a new one, suggested I can go with black pipe but he would do a brass section where the nipple is attached.   He also suggested to replace the muffler, he has installed a Veralift model that has both input & output on top.

What did you do for a replacement muffler?

I have flexible coupling is this the best point to disconnect the shaft?

[Ron Hill]

Ed : If you have the original riser - it black pipe.  Catalina didn't go to stainless until about hull #375?

I got my replacement muffler for Catalina factory. 
I'd be cautious about a different muffler especially if it has a smaller internal capacity than Catalina's.  Remember that you have about 17 feet of hose from the muffler to the exhaust exit.  At some point when you shut off the engine some?? of that water/gas mixture in the exhaust hose will flow back into the muffler!!! 

Just disconnect the flexible coupling from the transmission.

A few thoughts

[KWKloeber]

Ed : If you have the original riser - it black pipe.  Catalina didn't go to stainless until about hull #375?

I got my replacement muffler for Catalina factory. 
I'd be cautious about a different muffler especially if it has a smaller internal capacity than Catalina's.  Remember that you have about 17 feet of hose from the muffler to the exhaust exit.  At some point when you shut off the engine some?? of that water/gas mixture in the exhaust hose will flow back into the muffler!!! 

Just disconnect the flexible coupling from the transmission.

A few thoughts

Ed,

Understand that the pics you have of the muffler setup with the high temp silicone fittings etc., on the other catalina installs for the XP and Beta 20 is with the Westerbeke water-cooled riser that was upgraded on those boats from the Catalina 1-1/4" pipe riser.  It's MUCH better than the OEM riser and it requires a side-inlet muffler -- I worked the design out with Centek and the muffler capacity is as required for our size diesels.  The reverse-inlet absolutely eliminates ANY chance of back flow thru the exhaust valves when heeled -- the old riser/aqualift muffler with the top inlet still has a (very slim) chance of backflow -- which is why it's so oversized (what's required on the M25 is an 8" muffler -- Westerbeke even used an 8" muffler on larger diesels (Canadian Sailcraft 36 comes to mind with 30 and 32 HP diesels.) 

The Westerbeke water-cooled riser is the gold cadillac and is a significant upgrade from the hot iron pipe or stainless.   If you fabricate a riser, use Schedule 80 black iron NOT galvanized.  Also, the new Aqualifts are better built than the originals that were prone to many leak and self-destruct problems, but they are not as well made as Centek mufflers.

kk

[Ron Hill]

Ed : Take a look at the mufflers that Ken has suggested and then look at the space you have on your C34. 
Determine if they'll easily fit and how you'll make the connections from the engine and to the exhaust hose!!

Also examine the prices as well as remembering my mention of the capacity. 

A few thoughts

[KWKloeber]

Ed : Take a look at the mufflers that Ken has suggested and then look at the space you have on your C34. 
Determine if they'll easily fit and how you'll make the connections from the engine and to the exhaust hose!!

Also examine the prices as well as remembering my mention of the capacity. 

A few thoughts

Ron,

Understand that I'm not suggesting or recommending just "a muffler". This is in response to a "system" which is to significantly upgrade the "system" starting with the riser.   That leads to the connection to the muffler,  which leads to the muffler that "works" with that system,  which leads to the connection to the exhaust hose.   The theigh bone is connected to the leg bone,  which is........

If I were replacing only a muffler,  I'd likely use an aqualift,  but fix its flaws before installing it.

Kk

[Noah]

Ken- you said "If I were replacing only a muffler,  I'd likely use an aqualift,  but fix its flaws before installing it." What does "fix its flaws before installing it" mean?

[KWKloeber]

Ken- you said "If I were replacing only a muffler,  I'd likely use an aqualift,  but fix its flaws before installing it." What does "fix its flaws before installing it" mean?

Noah,

The OEM aqualifts had weak points that are prone to leaking -- notably the seam between the base and cover.   Though new ones are better made I would reinforce it IF I installed another aqualift.  Also the aqualift isn't reinforced like, say, a Centek, and the hose connection nippes are prone to crushing.  I had a pc of thin aluminum tubing that tapped snugly into the fiberglass tubes and allows torquing down the hose clamps without crushing the fiberglass.

See  the write up on repairing an aqualift on the techwiki.

kk

[Ron Hill]

Guys : If you use the Trident "hump hose" like I hope you are, there is NO need to "torque down" the hose clamp.  The was needed when the factory used a piece of wire reinforced exhaust hose!!

Ken : There have been many improvements in items like mufflers and water cooled risers and I looked at them when I installed a new engine.  The problem that a C34 owners is faced with is SPACE
People thought I was crazy to install a M25XPB (26HP) engine when for a few $$ more I could have installed an M35BC (35HP) engine. 
The simple fact is that the 4 cylinder M35BC engine would NOT fit in the C34 hull that was made for a 3 cylinder engine.  As it was I had to chisel out part of the teak steps to get the 3 cylinder M25XPB to fit!!  I sent the water cooled Westerbeke riser back because it would NOT fit and had to manufacture my own adaption rise to fit the space and align with the aqualift muffler.  All the room under the head sink was already taken up!!
It seems that the Catalina quietly redesigned the top half of the hull and part of the engine bed to accommodate the 4 cylinder engine.

So when I mention to c34 owners - look at the space available - I do not jest. 

My thoughts

[Ekutney]

I just removed the exhaust riser and water lift muffler, as said in previous posts the information on this site was invaluable.  Using PB blaster and patience made the whole process go rather smoothly.  My mechanic said the mounts were good but they are original OEM mounts and I plan to change them to K75s based on the positive comments made by others that have used them. 

I have run into an issue, I removed the lag bolts from the front mounts and found one of the lag bolts was considerably shorter than the other three.  It looks almost like the shorter one is broken but can't understand why it would be tapered at the end, I talked to the PO and he had the motor mounts changed a few years ago.  I plan to head back to the boat later today to see if one of longer bolts will work in the hole that the shorter bolt came out of.  When I closely examined the shorter bolt I can also see Epoxy on the end of it.  My fear is there may be a lag bolt brokeN off in the hole.  I don't want to have to pull the engine just to drill out that hole.  It had previously been suggested to put a bundle of toothpicks what are your thoughts?

[Stu Jackson]

Ed, that shorter one doesn't look broken at all, just, uhm, shorter.  No way to tell what or why any PO did something.  Just try a longer one before you mount anything and see what works.  Lag bolts are always pointy at the end, as are the others in you photos.

[Ekutney]

It looks pointed at the end but when examining it closer it looks modified.  I plan to head the boat in the next couple days to try and see if one of the longer bolts goes in further.  I talked to the PO and he had a shop change the mounts a few years ago and was not aware one of the bolts was shorter.

I do plan on using your "bunch of toothpicks" to give it more bite.

[Ekutney]

I need to disconnect the shaft from the engine so I can raise it in order to drill into the stringer.  I have done a search for how to disconnect the flexible coupling looking for pictures but have not found any,  there are explanations but it was not very clear.   A pic is attached to show what my configuration looks like.

Also the boat is in the water.