Exhuast Elbow

[saileagleswings]

Has anyone replaced the exhaust elbow or inspected it? I believe the elbow is a Westerbeke part; does anyone have the part number?

[Prairie Gold]

I have replaced my exhaust mixing elbow on my Yanmar 3YM30 - actually had a local service engineer do it for me. Total cost including labor was ~$500. It seems that the mixing elbow can cause some rpm issues and there are several online discussions about it. My max rpm dropped dramatically to about 2,200. I have also read that running the engine at low rpms is not good and can overtime lead to this problem. I now always run my engine at higher rpms. Good luck with your replacement.

[leigh weiss]

If you have the M35B engine I think the part you need is #200488 Check out transpacificdist.com about @$180.00. Double check with your engine.
It was easy to install if you replace the hose at the same time. About 1 hour and about two grunts to remove the hose from the water lift.

[MorningStar]

I purchased the water injection elbow for my M35B Universal based on the parts manual. Unfortunately it is "only "a water injection elbow with no riser built in. After checking the elbow/riser on the engine for a part number, it is casted "Westerbeke part # 367" which I can not find anywhere on the internet. The water injection elbow I purchased (45 degree) does not have the riser but only water injection. The part number in the parts book is 200486. It's not the same part that's on the engine. Has anyone replaced the riser is injection elbow? And if so what's the part number?? Do I need the riser?

Thanks,
Barry Dupuy
Kemah, TX.
s/v Morning Star hull #35

[KenKrawford]

Barry there is an article in the Technical Articles of the Members Only (paid up C350IA members) section of the web site that might help, It's from a Aug. 2011 Mainsheet writeup on the exhaust riser written by Bill VanWagoner.

[MorningStar]

Ken, Thanks for the input. Found the article. That's a big help.
Barry

[cuthbert]

I have just replaced the exhaust elbow and just like the mainsheet article, I cut the old one to pieces and inspected it. (sorry about the size I cannot control that).

The reason for doing so was that I had a small leak from the water pump, so small that there never was any water dripping/leaking but it did lead to staining the bottom edge of the wooden engine front cover. It had been doing this for years and I had never picked up on what the stain was until rust appeared on the pump body. In sending the pump to Depco in Fl for an overhaul I was told it was beyond repair and would have soon failed in a seizure of the engine, so it was caught just in time.

Replaced it with the oberdorfer due to price and easy access to the impeller and took the opportunity to replace all the hoses, clean, paint and pressure test the heat exchanger (and add the pad that seemed to be missed in initial production). I did not extract all the coolant, just that which came out in doing the job (3/4 gallon) and added green OATS style can be used with any type coolant from an auto parts store.

Bottom line - after 13 years and 1000 hours on the engine the riser did not need replacing (looks like it would last many more decades and thousands of hours) the hoses had not softened and the heat exchanger was equally in great condition. Some calcium build up around the hose ends/clamps and heat exchanger ends but from a mechanical standpoint I could have saved many hours and just changed the pump as I might in a car. But the peace of mind of going through everything and inspecting lots of parts close up was worth it.

[MorningStar]

Do you have any other photos from a different viewpoint. I have a new elbow and plan on replacing it this winter. Engine has 1900 hours, 13 years old. If available please send to my email, bjdupuy@gmail.com
Thanks,
Barry Dupuy
s/v Morning Star #35

[nybor]

Hi. Rats. Just got back from a 370 mile cruise to the Dry Tortugas from Venice. Going was great, coming back not so. The engine ran fine down to the fort, but coming back it started to overheat. Had to tow it the last 15 miles (thank goodness for SeaTow)

Anyway, checked the strainer, changed the thermostat, impeller all ok. It seems it is not getting enough water. I did have a clog in the intake and boy, did the dingy pump work! But the temp still climbs. I noticed a white smoke as the temp goes up. Not sure if it is condensation (fog) since the air temp was 50 degrees this morning (yep Florida). But the water coming out comes in spurts and not very much.

Any thoughts. I was trying to locate that Mainsheet Tech article, but don't know how to get to it from.... from where?

thanks

dave
ps. I am not at the boat, but can someone tell me where is the exhaust elbow located? can it be cleaned?

d

[wolfe10]

With your symptoms, first thing is to check the raw water impeller. Second is to check the raw water strainer. Third would be to pull and "boil out" the heat exchanger.

[nybor]

thanks. did the impeller and the thermo. I will do the heat exchanger next

dave
ps i STILL don't understand about the aqua-lift/exhaust elbow thingamajig.

oh well

[Mark Sutherland]

Check the integrity of all the hoses. Are all fittings tight, any cracks or leaks? I'd also consider changing the impeller before I removed the HX.

[atorino]

I had similar symptoms a couple of years ago. Turned out it was barnacles covering up the intake. The intake hole is quite small and easy to clog. Suggest you look at the underside of the hull.

[nybor]

update. I removed the heat exchanger and the small tubes looked clean (I had replaced it two years ago). So, I am going to put the original one back in. However, I did notice that when I tried to remove the last hose (the one on top coming from the coolant tank, there was some cracks in it. I had noticed a couple of drops of antifreeze on the floor, but once the engine heated up, it went away.

Is it possible that such a small crack could let enough air into the heat exchanger to cause the overheating? What I don't understand is how that is related to a lack of water flow out of the exhaust? I guess if there is air, it could cause cavitation inside the exchanger.

Anyway, ordered a new piece of hose. will install next week. Stay tune for exciting news on this channel...


dave

nybor

[ldirubbo]

I had my exhaust Elbow replaced last year. Mandy is 2004 hull 235. I went to a talk at one of the local yacht clubs and they had examples of the build up in the elbow, It can clog as much as 50% over a period of 10 to 12 years. It was recommended checking it out and replacing it needed. Another Catalina owner I know had his changed last year. The speaker was a well known marine diesel center that sells parts and has training class so it wasn't as if they were looking to do the work on our boats.

[wolfe10]

Dave,

Crack in a hose on the CLOSED SIDE of the cooling system has zero affect on water volume on raw water side.

As discussed, potential restrictions in the raw water side are:

Marine growth in the intake (below thru hull)
Clogged filter strainer
Kinked hose
Bad impeller in raw water pump
Previously broken impeller blade stuck between pump and heat exchanger
Heat exchanger (which you have ruled out)
Exhaust elbow
Kinked hose to muffler
Clogged muffler
Kinked hose muffler to hull side

[Triumph]

I would usually suggest the elbow too. However, because it ran fine on the way down, then overheated on the way back, this may not be the cause this time. That symptom doesn't usually happen so suddenly, it slowly worsens over time.
Check this. If you have a 90 degree bend in any of the hoses leading from the exterior intake to the water strainer, there could be a pile of sea grass jammed in the 90 degree fitting. This could be the restriction. This includes the one right before the strainer, or attached to the strainer. Use a coat hanger with a hooked end to fish for this.

The voice of experience,
TRIUMPH

[nybor]

Boy, what a great forum! Thanks to the above responses. Yes, it was strange that it occurred "suddenly". I will definitely check the elbow fitting into the strainer.

In fact, got to thinking that we went through some strange sea grass particles when we arrived at the Fort. They were dispersed (not concentrated), but the pieces were pretty thick. Almost like thick spaghetti. I can see how that would or could get caught in an elbow.

I did order a new exhaust mixing valve. The boat is 11 years old so probably time to do so. I will have the old one pickled and keep for a spare.

thanks again for all the support.

dave

ps. Ken, just wanted to verify that you are paying us postering folks $50 a word? My last post was worth $890, but haven't seen a check yet. Is it in the mail?

d

[zman18]

I have the M35B engine on the boat and I'm trying to determine if/when to replace the exhaust elbow. Does anyone know if there is any info on when to do this maintenance such as: engine hours, years, outward appearance of the elbow, etc. The articles I've seen are all over the board and the manual just mentions replace as necessary. Currently my cooling system is working fine and there is no outward appearance of problems on the elbow.
Thanks
John
Compass Rose
Hull 484

[russp]

Hi John,
Based on my experience there is no way you can check the state of the exhaust elbow from external appearance, you have to remove and inspect internally. When mine was taken off it hadn't perforated internally, but had deep pits and the mechanic said "time to replace". That was after 12 years and 1200 hours on engine.

I don't think you will see any effect on cooling system unless it blocks with carbon, but if you get salt water leaks back into exhaust manifold you will regret not changing it sooner.