Motor mount and exhaust riser (with flix)

[Mike and Joanne Stimmler]

I have been having an increase in engine vibration fur the last few months and at first thought that it was related to the recent cutless bearing replacement but on closer inspection I've found that my forward starboard motor mount is bad.
Also Ken Heyman pointed out while he was visiting with us a while back, some water that was around the muffler at the exhaust riser hose connection. I traced this later to a small hole in the exhaust riser, just above the hose connection which I was able to temporarily fix with epoxy putty.
So, it looks like it's time to replace motor mounts along with the exhaust riser and hump hose.
I've been reading the threads and it looks like most are using the vetus k50 or k75. Is there a better choice of one over the other? Has anyone tried to use the factory mounts from Universal?
On the exhaust riser, will the one from Catalina Direct be OK? As others have noted,  Catalina Parts requires that you send the old one to them to copy, Catalina Direct doesn't. I'm concerned that the one I get will fit and do I need to replace the flange or reuse the old one.
Catalina Direct looks like the best source for the 8" hump hose, which I understand will reduce vibration as well.

Any help will be appreciated,
Mike

[Stu Jackson]

Mike,

Exhaust riser:

1.  Here's the link to my 2003 riser replacement in Tech Notes:  http://www.c34.org/mainsheet/pdf/Feb_2004.pdf, and an earlier topic: http://c34.org/bbs/index.php/topic,5846.0.html

2.  Here's a picture of the flange when we removed the riser in 2008 to get rid of the blow by.  We were able to reuse the existing flange.  Don't forget to buy TWO gaskets, read the link above.

3.  Be careful about ordering from Catalina Direct.  They're good, but unless you KNOW what they're offering, you must be aware that there were two versions, one for the Mark Is and a different one for the Mark IIs.  I'd call call them to confirm since it's hard to tell from the pictures on their website what they are offering.  Your Mark I will need one like the photo below with the bend to get to the flange.  I ordered mine from Catalina without sending the old one in, I spoke to Robert Butler in 2003 and faxed him the drawing, also shown below.

Hump Hose

CD seems to be only place to get it these days.  1 5/8".  Picture below with old broken riser.

[Ron Hill]

Mike : Lets take your questions one by one:
On the exhaust riser much has been written.  I'd go with Catalina (send them your old one) or have it made locally so you can get an exact match of the old risers' dimensions.  You can use the old flange and most important is that the flange has the same orientation as the old one.  Catalina factory & locally will do that - you'll have to do it if you go with Catalina Direct.
The biggest problem with the re-installation is making sure that the mating portions for the flange on the engine MUST be perfectly clean before installing the gasket. As I mentioned 15+ years ago - get 2 or 3 gaskets ($2.50) as they are very easy to screw up.  Get new hardware (nuts/bolts) for the top two studs and new for the bottom - as you'll probably have rounded the heads and it will save you grief in the future.

On engine mounts - I'd use K 50s on the front and K75s on the rear.  Or just get K75s all around.  If other M25XP owners have changed out their mount they really haven't shared their outcome.  I sure wouldn't get new ones of the same make as the OEM originals were!!  Any other mount would be better than those!!  

A few thoughts

 

[Mike and Joanne Stimmler]

Thanks, Stu and Ron.

BTW, the OEM mounts are $150, and the Vetus mounts are $76.50

[Ron Hill]

Mike : I have a couple of thoughts I want to pass on. 
When you get the new stainless riser make sure that the nipple for the raw water entry is stake welded on the inside.  That's extra reinforcement.
Use a nylon reinforced NOT wire reinforced 5/8" hose for the raw water from the anti syphon to the nipple in the riser.  The wire reinforced hose will transmit all of the engine vibrations to that nipple.  The nylon hose (on the exhaust side with no acute turns) will transmit less engine vibration to that nipple = less stress on that nipple.

Both of the above are designed to get increased life out of the riser, as that nipple weld is usually the first thing to go.

When you install the riser, make sure that there isn't too much insulation on the engine end of the riser so it puts pressure on the heat exchanger.  Take a Dollar Bill an make sure that there is clearance between the two!

A few thoughts.    

[Tom Soko]

Mike,
When I replaced the motor mounts on Julandra (M25XP), I used K75s on all four corners.  The results were spectacular.  Much quieter and smoother.  As Ron has described in the past, you will need to ream out one of the two holes on each mount to allow for adjustment.  Easy to do with a round file or Dremel.  Not that big of a project, but it made a HUGE difference.

[Mike and Joanne Stimmler]

I'm not sure I understand how the exhaust riser works.
One of the instrustions in changing it says to drain the antifreeze out of the manifold. I thought that only sea water was going through the riser to the muffler along with exhaust gasses. Am I missing something? Do I really need to drain the antifreeze?

Also, looking at the motor mounts, it looks like the hardest one to get to is the rear port side. Can they be changed without disconnecting the shaft and if the exhaust riser has to be disconnected, I would think they should be done at the same time.

'Splain it to me   

Mike

[Stu Jackson]

I'm not sure I understand how the exhaust riser works.
One of the instrustions in changing it says to drain the antifreeze out of the manifold. I thought that only sea water was going through the riser to the muffler along with exhaust gasses. Am I missing something? Do I really need to drain the antifreeze?

'Splain it to me 

Mike the exhaust gas comes out of the aft of the manifold.  The riser attaches to the flange which is bolted with the three bolts (the hardest one is the bottom one) to the back of the manifold.  The manifold is also full of the freshwater (antifreeze) coolant.

The water that goes to the exhaust riser nipple comes from the HX and goes to the nipple under your head sink.  That's seawater.

Clear enough?

When we redid ours, we didn't carefully install the gasket between the manifold and the riser flange (the bottom hole in the green gasket is very, very close to the edge of the material).  When we started up it began to leak that green antifreeze.

That's why you need to drain the antifreeze.  Do what I suggested in the burping thread, (Reply #6:  http://c34.org/bbs/index.php/topic,4518.0.html) and remove it through the hose under the freshwater engine pump right from the front.  Much easier and less messy than the block or the HX connections.

[horsemel]

So Stu, I still have the frozen bottom bolt on my riser I posted about some time ago.  I was intending to deal with the issue after the boat was on the cradle.  If I understand you correctly, I will lose the antifreeze out of the manifold when and if I finally get the riser off. Correct?  I understand that the manifold has antifreeze but was not aware that the antifreeze comes out where the exhaust does or does it come out where you remove the three bolts?  Just trying to avoid a mess
Mark Mueller

[Ron Hill]

Mike : Let me try to explain the exhaust riser and the flange that attaches to the engine. This is only true for the M25 & M25XP engines.  

The piece on the top port side of the engine with the "radiator cap" is a duel functioning unit.  The top part is a reservoir that hold the 50/50% Prestone water mix for the engines internal coolant.  The bottom part of that unit attaches to the side of the engine and is the exhaust manifold from the cylinders.

So when you remove the flange & gasket (3 nuts) at the rear of the "reservoir unit" there will be two openings.  The top one will be to the the coolant chamber and the bottom is to the exhaust from the cylinders.  The gasket that I talked about is solid to cover the coolant opening and has a square hole for the exhaust to go thru.  (I suspect it was made like this because it was a sand casting and the coolant hole was where they got the sand out - this is my assumption)

The gasket is duel purpose: to seal the coolant in the reservoir and seal the exhaust gases so they go out the riser pipe - eventually to the muffler.

That's why it's important to make sure that you drain the coolant before you remove the flange and the old gasket, because if you don't the coolant will run out and soak the port rear engine mount.  Draining the coolant is no big deal.  You can do it as Stu suggests or use the petcock on the starboard side of the engine just under the injection pump.  Attach a hose to the petcock , open it and with the cap off the  coolant will drain out into your container. Still use plenty of rags under the flange to catch any residual coolant .

When you put the new gasket back ON, make sure that both metal surfaces are ABSOLUTELY CLEAN !!

When the engine is running the raw water moves thru the HX and cools the 50/50% internal mix that is inside tubing - the raw water flows on the outside of those tubes.  The heated raw water goes out of the HX to the antisyphon valve and then is injected into the hot air exhaust gases (thru the nipple in the riser) just before they both enter the muffler.

Hope you now understand the way the riser/HX work.

Now picture me taking all of this apart (by myself) 15+ years ago, no internet, nothing written and no one to ask.  When the coolant started to leak I learned fast!!  

A few thoughts. Good Luck!!

[Stu Jackson]

Like this

[Mike and Joanne Stimmler]

Thanks Stu, your pictures clarify things. Looks like the riser flange blocks the 50/50 antifreeze and just passes the exhaust gasses but when the flange is taken off, there is an opening to the reservoir that would allow the antifreeze to pour out if you didn't drain it.
I think I've got it and thanks to all that helped.

Mike

[Ron Hill]

Mike : Yes, it's the combination of the gasket and the flange pressing against the gasket that holds the antifreeze coolant in the reservoir.

Stu's second picture also shows bluish green residue of the old gasket yet to be cleaned off.  You'll find that residue on both the flange and the back of the reservoir.  BOTH surfaces must be clean to get a good seal.  The back of the reservior is difficult to get to !!
As I mentioned before, it's better to have thin insulation on the riser just above the HX or the flange will not completely seat!!  Catalina really screwed me up as they put a thick layer on the my replacement riser.  I seated the gasket, inserted the flange and tightened everything down.  As I was refilling the reservoir I noted that the coolant was running out!!  The insulation wouldn't let me tighten the bottom nut completely to the gasket & reservoir.  That's why you need to make a "dry run" in attaching the riser and make sure that you can slide a $1 bill between the bottom of the riser and the top of the HX.

Really not that difficult.  Just Don't forget the hump hose and the nylon reinforced hose to the nipple. 

[horsemel]

Thanks guys, In this case a picture is worth about four million words.  We just finished having AC installed (16000 btu) and have discovered some major problems in the electrical panel (more on this later), as a result so the riser issue is on hold until late Feb or March.  I would have had the riser issue handled except for the frozen bottom nut!  I will keep soakiing with PB over the winter, but I really think I will have to use a nut splitter on it.
Mark Mueller

[Mike and Joanne Stimmler]

I was able to get the exhaust riser off last week thanks to the help of this board.   

First I used multiple liberal applications of PB Blaster with a Q-tip and at first was able to get the two top nuts loose but not the bottom one so I re-tightened the top ones and went out for a day sail and after motoring back in and another application of PB Blaster and waiting about an hour, I was able to loosen the bottom nut with a box wrench from the port side of the motor.

My idea here was to let the heat of the engine help the PB Blaster to penetrate the nut and it seems to have worked.

I was then able to get the old non hump hose off after removing the (double)clamps and twisting the hose with channel lock pliers at both ends and the 3/8 inch water inlet to loosen it and was then able to slide the old hoses off without having to cut them. As mentioned in other posts, you must be careful with the hose connection at the muffler so you don't crack it.

I was able to separate the flange from the engine by simply wiggling the riser from under the sink. The clearance was a little tight moving the flange end away from the engine because the lower flange stud is a little longer than the top two but with a helper we were able to remove the riser through the door under the sink. We really didn't try to remove it through the engine compartment, and it may be possible, but it just seemed easier from under the sink.

I have already sent the old riser to the Catalina factory and am waiting for its return.

One question is can I/should I use a permatex type gasket compound on the flange gasket? That question also goes for the gasket on the raw water pump cover.

I just got the 4 new K75 engine mounts in the mail so I will try to schedule doing both jobs at the same time since I think the exhaust flange has to be off to do the motor mounts.

I'll let you know how the rest goes.

Mike