Steam in exhaust M35B

[Mick Laver]

A couple of months back I posted a gleeful message that Oberdorfer had come out with a new model of raw water pump, the N202M-908, that is a drop-in replacement for the dreaded Sherwood G908. This seemed like great news for M35B owners who were fed up with the poor quality and maintainability of the Sherwood but didn't necessarily want to do the necessary surgery to modify the Oberdorfer N202M-16 to fit an M35B.

I got one of the new Oberdorfers from DEPCO and promptly violated RULE 1 by installing new untested equipment on my engine before a long trip. Dumb. With some friends (also on a C34) we headed out to Ensenada from San Diego, about 62nm. All was well until about the last hour when I noticed steam coming out the exhaust. The engine temperature was fine so we continued to the marina (Cruiseport) and I promptly forgot about it (thus violating RULE 2 - if something's broken fix it.) A couple of days later we started the mini-bash back to SD and the steam started earlier, probably because the engine was working harder going against the current. Again, the engine temperature was fine, but I checked the temperature of the exhaust hose coming off the riser and where it exits the boat: neither were usually hot to touch, so we "steamed" back to SD.

Once back I did some research, and it seems the main cause of steam in the exhaust is insufficient water being injected into the exhaust at the riser. What changed? The Oberdorfer, of course. It doesn't put out as much water as the Sherwood, and apparently the small difference was enough to cause the problem. I checked this by going out the day after we got back by running the engine to operating temperature with the Oberdorfer and verifying the steam problem and then swapping back my Sherwood and doing the same test. No steam.

I called Oberdorfer and asked what the flow rate was for the N202M. The person I talked to said he wasn't sure, but "probably 9-10 gpm." When I described what had happened he suggested that that pump was not on the "recommended list" for the M35B. I called DEPCO and without hesitation they asked me to send the pump back and they'd issue me a credit. This with 30 some-odd hours on the pump - great company.

I still wanted a backup pump, though, and since Ken Kloeber had offered to provide dealer pricing for raw water pumps to C34.org members I contacted him about the cost of a new Sherwood. This started a long (and still ongoing discussion) about why the Oberdorfer wasn't working for me when many others had made the swap. Ken volunteered to send me an Oberdorfer to test, but that's a whole separate discussion. (5 second summary: The Oberdorfer puts out about 20% less than the Sherwood and neither put out anywhere near 9-10 gpm at an M35B's normal operating rpm.) Ken had a very good question for me, and that's what this post all boils down to: Since the Oberdorfer is such a superior pump to the Sherwood, what's the harm of a little steam in the exhaust if the engine's staying cool? I'm thinking not much.


- Mick

[Stu Jackson]

Since the Oberdorfer is such a superior pump to the Sherwood, what's the harm of a little steam in the exhaust if the engine's staying cool? I'm thinking not much.

Mick,

I'm truly sorry you had such a bad experience.

However, I have to share with you the fact that this "flow rate" stuff has been around for years and makes little sense.

Why?  Because it makes NO sense on its merits.  IF the O flow rate was not enough to make our engines work, how come IT SIMPLY does work on those engines in which it is installed?  OEM or retrofit. 

The Sherwood is an inferior pump simply because it is made from too many parts with too few reliable parts.  That's even before you start to deal with faceplate/backward screw issues.

OK, I'll admit, I only have a puny M25, but my Oberdorfers have been working for 17 years.

Universal made the engines with both, IIRC.  I'm glad I got an O but would have quickly swapped it out if I had an S once I started reading Mainsheet magazine.

So, let's go to your engine.

The original article about the swap from S to O was from some very good C36 owners.  IIRC (without rereading the wiki article) it was for an M35.  They've (Oberdorfer) since (just recently) made a pump that doesn't require trimming the base.  Nonsense: buy a pump that's 50% of the price and trim it yourself.   Why pay them?

Why have so many folks been so impressed with their "improvements' by swapping our their Sherwoods for Os?  On M25s, M25XPs, M25XPBs and M35s? 

IIRC, Depco's website has ALL the pump specs online.  Have you checked there?

If I was you, I'd be looking elsewhere for answers, 'cuz they ain't in the pump.

You could also check out an advanced search on Oberdorfer with my name and read some more.

There's also a tad of information in the tech wiki.

PS - Engines don't "work harder going against the current."  The work that engines do is simply based on the position of the throttle.  The engine could care less about whether it's +2 or -5 knots outside the boat.  If your engine temperature was fine, what's the issue at all????

PPS - Have you considered that you may have had a "dud" pump?  They took it back.  DEPCO's great.  Did you replace it?  Or are you still discussing this with Ken, who, I'm sure would tell you a Sherwood is a piece of crap?  Or many pieces of crap.  Any issues with your HX?  How old is your exhaust riser?  How old are your rw hoses and exhaust hose?  I'd look elsewhere.
 

[Ron Hill]

Guys : No comment -- as I said it all before!!! 

Ask Westerbeke

[Mick Laver]

Thanks all:

Ron - I'm not exactly sure what I'm asking them! I suspect they'll say "We specify the Sherwood G908 for the Universal M35B. That's what you should use. Ugh. If you have a contact I'd be happy to follow up.

Stu - Yes I understand about the engine not caring about the current. I should have said current and the swell. We were headed into a 1-3 chop (if memory serves). Your question "if the engine's not overheating what's the problem?" is exactly what I'm asking. I get constant steam out the exhaust but I'm able to use a far superior raw water pump. The hoses aren't hot, the engine's at 160 degrees. What's the drawback other than it doesn't *seem* right?

As far as the O being a dud, Ken did supply me with a new one to test after I had sent the one I took to Ensenada back to DEPCO. I had the same issue with the new one.

FWIW the surface water has been freakishly hot in southern CA. The problem may go away when its back to its normal 55-65 degrees. That said, I'd be curious if M35B owners in FL (or anywhere else "warm" for that matter) have seen this issue with the Oberdorfer.

[Ron Hill]

Mick : I'm not getting after you at all.

I've had personal experience with both the O and the S raw water pumps.
 
As ALL know, I've written articles about both pumps and am the only person that has told others how to rebuild each of these pumps. 
Most others criticize with only knowing what some others have written and expound on that written word - rather than on their own personal experience.

Westerbeke will tell you that the Sherwood pumps more water (as you and I know). There are other advantages to the Oberdoffer, but pumping water seems to me to be the primary purpose of the pump that the engine manufacturer selected for their engine to keep it running cool.

Enough said!! 

[Stu Jackson]

1.    and am the only person that has told others how to rebuild each of these pumps. 
Most others criticize with only knowing what some others have written and expound on that written word - rather than on their own personal experience.

2.  Westerbeke will tell you that the Sherwood pumps more water (as you and I know).

3.  There are other advantages to the Oberdorfer, but pumping water seems to me to be the primary purpose of the pump that the engine manufacturer selected for their engine to keep it running cool.

Ron,

C'mon already.

1.  Thanks to your guidance, many of us have rebuilt our pumps.  I meticulously credited your groundbreaking articles on pump rebuilds, but also provided a detailed photo essay on how to do it, right here on the forum, and linked the the "101 Topics."  We know: if it needed to be done on a Catalina 34, Ron Hill wrote it up.

2.  We know that, too.

3.  The same engine manufacturer chose to put Oberdorfers on most of the same engines, too, except perhaps the M35.  But a significant number of skippers have swapped out the crappy Sherwood TO new Oberdorfers and have been quite satisfied.

I have not yet questioned Mick's issue of "steam", so, Mick:  What were the atmospheric conditions at the time?  You said the water was unusually warm, and asked a great question about skippers in normally warmer waters.  Could it have been mist instead of "steam?"  Have you considered getting in touch with the skipper who wrote the wiki article?

[Ron Hill]

Mick : I see that others have taken offence with our correspondence!!

BTW, the M25 and M25XP engines were built by Universal Oshkosh (with Oberdoffer, Johnson & Sherwood pumps).  Then Westerbeke bought Universal from Oshkosh (early 1990s) and produced the M25XPB and M35 series engines - all with Sherwood pumps.

If you want some expert advice talk to Joe Joyce, Westerbeke Service Manager @ (508)832-7677 x234.
"When you talk to the manufacturer, you are talking to the horses mouth. When you get info from the internet/blog you don't know which end of the horse is talking!"  A Ronism

"Let your personal experience be your guide".  A thought

[Craig Illman]

A different tack..... Does anyone know what raw water pumps Beta uses on their marinized versions of Kubota blocks? Maybe there's a third alternative?

[KWKloeber]

If you want some expert advice talk to Joe Joyce, Westerbeke Service Manager @ (508)832-7677 x234.
"When you talk to the manufacturer, you are talking to the horses mouth. When you get info from the internet/blog you don't know which end of the horse is talking!"  A Ronism

Settle down boys!  This technical discussion has taken the political tact of Sw vs Ob personal preferences and has taken on some misinformation.

With all due respect to the vast knowledge about C34s, some FACTS about the question on using an Ob pump vs a Sw pump:

Westerbeke will tell you NOTHING except "use the Sherwood 908" because:

   Wb will never recommend anything EXCEPT OEM parts.
   Besides, asking that of Wb is like asking your Ford dealer, if they recommend a Chevy.  C'mon, really?
   Wb dealers are LEGALLY PROHIBITED from offering ANYTHING but Wb OEM parts for Wb engines -- they will lose their dealer or distributor status if they do.  If you think otherwise, I can privately email the dealer/distributor agreement.
   Wb legally has EXCLUSIVE rights to the Sw G-908 pump, it is an exclusive Wb dealer/distributor part, and is price controlled.  Sw can't even sell it direct at the Wb list price!  That's how/why Ob can stick it to (up) owners with the outlandish price it is charging for its ("new') M-908 pump which is simply the M-16 pump (casting machined round instead of drilling it for M-16 style base.)
   Wb forced Sw to stop production of and selling the former G-903? pump that was on M25s et al, because of the infringement on Wb's rights.
   The B series engine land does not FIT the (former) Ob pump bases (M-16, etc. -- so there's no argument that Wb would have used an Ob if it worked correctly.)


Another post coming re the actual technical issue of temp and steam.


Cheers,
Ken
the pump guy

[Stu Jackson]

1.   The B series engine land does not FIT the (former) Ob pump bases (M-16, etc. -- so there's no argument that Wb would have used an Ob if it worked correctly.)


2.  Another post coming re the actual technical issue of temp and steam.

1.  Ken, FYI the C310 skippers have M25XPB engines, and have just written up their swaps to O pumps from the Sw's.  It's over on co.com. 

http://forums.sailboatowners.com/index.php?threads/universal-m-25xpb-sherwood-raw-water-pump-questions.139566/

2. Looking forward to that! 

For those of you new to us here, the O swap out is in the tech wiki, here:

http://www.c34.org/wiki/index.php?title=Replacing_a_Sherwood_Water_Pump_with_an_Oberdorfer

[Stu Jackson]

In the link in Item 1 in my last post is a reply from a friend of mine in Florida, which might help to answer Mick's original question about steam.  "Captain Ron" is a fine old curmudgeon, like me  ,
and here's his reply.  Please note that this may be somewhat similar to the age-old issue with our M25 engines that came with the 2 inch HXs.  I upgraded our HX to the 3 inch HX that comes standard on the M25XP.  Captin Ron has a C30.

   

    Guy,

    I've read alot here about flow rate questions/advice between the Ober & Sherwood pumps.

    I don't recall what the Sherwood flow rate was on my 3M20A, but the Ober was rated @ 9.3 gph.

    Water in Florida in summer can get into the 90 degree range, so engine cooling is very important here.

    I had some high temp. readings with my out of the box engine when I first got it.

    I remember re-checking everything over & over to no avail, and finally really started to look at the heat exchanger.

    What I found, was that the heat exchanger was underated for the engine. I believe the orig. was a 2 pass type. I contacted Sendure Inc. who makes these. I downloaded their generic shop drawing and revised the in/out connections to agree with my hose & needed zinc connections.

    I had them make me a 4 pass HE with a 3 1/2" dia. outer shell. After installing it, my water temp. never goes higher than the OEM specs. It sticks @ 165 degrees no matter what time of year I'm runnung in.

    Some thoughts that if you're concerned with flow rates, or maybe running alittle hot, check to see what the OEM supplied.

    CR
     

[KWKloeber]

1.  Ken, FYI the C310 skippers have M25XPB engines, and have just written up their swaps to O pumps from the Sw's.  It's over on co.com. 

http://forums.sailboatowners.com/index.php?threads/universal-m-25xpb-sherwood-raw-water-pump-questions.139566/

2. Looking forward to that! 

Stu,

There's several write ups and pics online about the M-16 pump refit for the xpb.  But no concise instruction nor any template (that I found) to do it.    I had even contacted the ones who did the switch to see if they had kept a record of the dimensions/shape (they hadn't.)

There's ABSOLUTELY no problem using the M-908 (or remanufactured M-16) on the M25xpb... it's just seems to be the 35B with higher HP and heat generated -- I have heard of only one issue (Mick's).  And I can't yet say 100% that it's due to the larger engine (though it appears that way.)   And there appears to be no issue with the engine, manifold, injection elbow, or hose temps -- just the :steam: out the thru hull.  I hesitate getting deep into the technical discussion on that just now - because there's a lot of :unpublished: info on the tests and results that I want to go over.
  Suffice it to say right now, that Mick went WELL above and beyond was would be expected in cooperating on this, and devising reasonable tests of the Sw vs Ob -- In both the flow tests and the in-operation cooling tests, and is keeping an open mind.  Sincere kudos and a big thank you shout out to Mick.  I sense some engineering is in the genes.

As you may recall a while back I had started a beta test and remanufactured two versions of the M-16 pump to fit the M25xpb -- a round 'Sw clip-on base," and a machined "bolt-on base."  I posted the pics previously.  The beta pumps fit perfectly on the xpb, and one beta is currently still on a C30 and cooling like a champ ( my bolt-on version, which is superior to using the stupid Sw clips.)  The cost would have been about 40 bucks on top of the M-16 pump, and I would post the procedure and a PDF template -- if owners wanted to save the $40 and do it themselves.  Hopefully they would buy one pre-made, but if not, having the template at least they would get it correct "the first try."

Unfortunately, I showed Depco the pics (should I have called it the K-908??) and 6 months later Ob was selling their own version (round base only.)  Coincidence?  Ob was going to "get back to me" with a cost to purchase raw Ob M-16 castings (so that I could do the bolt-on base version,) but Ob won't even acknowledge the request anymore.  No wonder -- since OB can now charge $400 (M-908) for a $280 (M-16) pump.

Another issue I have with the applications for both the Sw and Ob pumps (on all the M engines) are the hose barb elbows.  They are brass -- a no-no for salt water and they are too short to double clamp.  There are no bronze hose elbows or straight fittings that are appropriate - I have a box of about $150 of hose barbs I have bought and evaluated -- they are crap and I won't sell any of them.  I have supplied some pumps with glass-reinforced hose barbs (somewhat similar to Marelon glass reinforced) but the problem is that 1/2 npt x 5/8" barb are unavailable.  Well, my supplier will make them for me -- the 1st one is $10k, the second copy one is free.  I have done some with 1/2 npt x 3/4 hose barbs and 3/4" inlet hose.

There's some bad info and a lot of "incomplete info" out there re the switchover.  To make my point the SBO skipper went to undue PITA trouble and heartache with those elbows and the Rube Goldberg he ended up with -- the OEM B series elbows can be reused with no issue (besides them being brass) -- a simple mod with a file or dremel -- but he didn't have that info at hand (apparently) so went through unnecessary work and time.

Yah still have that fuse in place? 

Cheers,
Ken

[chrisyse]

Where can I find discussion of How to determine cause of steam in the exhaust"?  I recently observed steaming from my 1989 25XP 2 weeks ago after reaching 160F. During initial pressure test of the engine water, it took 3 minutes for P to drop from 14psi to 9psi on a radiator tester attached to water access inlet on the exh manifold. I was unable to detect water coming from any cylinder with glow plugs removed. No overheating, engine temp stays at 160F, though steam is visible above 2200 rpm after engine reaches 160F.  I plan to repeat pressure test with engine cold, and if pressure still drops and no water observed in GP holes while spinning engine, I'll isolate HX and exh manifold and pressurized them. Calder's book suggested 2 causes, head gasket leak or unburned fuel. steam looks like water vapor. This discussion sound like 3rd possibility is low flow at mixing elbow which might be determined by measuring temp of the elbow. Am I on the right track? 

[Mick Laver]

I may be missing something, but why are you pressure testing the fresh water side when steam is coming out the exhaust (the raw water side)? Are you losing fresh water?

If it truly is steam, my bet would be insufficient raw water being injected into the exhaust riser ... my problem. Likely causes is a clogged HX or occluded raw water hoses. In particular you might want to check the hose coming off the HX that heads to the riser via the anti-siphon loop. I've attached a pic of what mine looked like prior to my swapping out ALL the hoses. Yuck!

[mark_53]

I had steam coming out of the exhaust recently. The cause was insufficient raw water being pumped into the aqua lift muffler due to 1) clogged raw water screen 2) blocked raw water thru hull, and 3) raw water impellor was not spinning because the brass insert in the impellor was spinning freely.  The first two items probably lead to the impellor problem.