low engine rpm

The starboard side locker is the right place. My refer compressor is no longer there as the new one is not a threshing machine noise wise. It is now under the galley sink. It's still crowded up there at the front of the locker. the check valve would be visible behind the engine or near the shaft log. There is no room on the other side of the bulkhead before the exhaust reaches the muffler.

I am off to look for the muffler. I have two refer compressors, this boat was really set up for cruising by a previous owner. The compressor for the port refer is under the settee cushion just forward of the sink galley, that one needed a recharge but now seems to be OK. The area under the galley sink seems to crowded to fit an compressor.

The starboard compressor for the refer (freezer just aft of the Nav table) , is on top of the hot water heater in that starboard cockpit locker. The compressor for that refer is dead and I dont plan to use it so I might just cut the freon lines and remove it altogether. That would provide access to the muffler, assuming as you say, that is where it is.

I do not see any check valve near the dripless stuffing box or log shaft. As I indicated, there is a reducer fitting, probably bronze, in that area, reducing the exhaust hose from the rise to something smaller, maybe from 2" to 1 1/2" or whatever, and that maybe because of the smaller hose size for the muffler. But that reducer does not look like a check valve, i.e. no pins or shafts visible from the outside, when I get the 2" hose off that reducer (to change out the riser), I will look up into the reducer to make sure it is just a reducer.

Another curious thing about the exhaust piping. On my previous boat with an A4, great pains were taken to have a rise in the exhaust piping BEFORE the mixing elbow, the so called "hot section" with lots of insulation on that pipe. That rise was to prevent cooling water from flowing back into the engine. And lots of warning to close the raw water intake in case the engine did not start quickly, to prevent flooding the engine with raw water, a common occurrence. On my E34, there is no rise in the exhaust plumbing before the mixing elbow, just a 1 1/4 nipple connecting the exhaust flange to the mixing elbow and not even any insulation on that nipple. The output of the rise is pointed downward so that helps but is this exhaust piping situation normal for Ericson??

Good luck with the muffler. It's interesting to see how many approaches there are to the exhaust system in the same boat. Mine reduces just behind the manifold with a 2" X 1 1/2" elbow and my mixing unit is 1 1/2".

Loren turned me on to the Isotherm refer units when my old dinosaur of a unit died. They are superbly compact and whisper quiet. The galley unit tucks under the bottom drawer and I added a teak vent above the drawers to ensure adequate airflow. The unit for the freezer is going under the chart table at the front of the icebox. There is still legroom. The systems are precharged also. No need for a refrigeration tech either.

Engine RPM

Hi Herb
I would bet that you do not have one of those check valves. Bob's advice is exactly where my de flappered check valve is. The Ericson Engineers told me to get rid of the check valve in 1982 so your newer boats theoretically should not have it? That being said I think have seen owners mention the check valve with boats newer than 1982.
Best Regards
Pat
1981 E28+ Chips Universal 5411

Do not rev that diesel up without a load! bad bad idea. A diesel will tolerate high load much better then high rev's.
#1 prop pitch should achieve 3000 rpm with a clean hull / hull speed.
Cables #2 exhaust#3
Lastly all one has to do is read the manual to find out that max rated RPM is 3000 for the M25 / Mxp25
cruise RPM should be 2100-2600

Capt. Ian

thanks Ian, I did rev up the engine both with and without being in gear, just quickly, I agree revving it up in neutral not a good idea. In neutral I got 2500 rpm and in gear at the dock, 2200 rpm, in gear underway also 2200 rpm. Last season I was able to rev up the engine in gear and underway to 2500 with some more throttle left to go. So I dont think it is the prop nor the bottom, but according to the cryptic notes in the log book, some previous owner also had a "rpm problem" and had the exhaust riser-manifold changed. I think he meant the exhaust mixing elbow. That was in 1999 at 1240 engine hours, it is now 18 years later at 2400 engine hours, it is probably the elbow being clogged. I have a new one on order, what I need is a gorilla to get the 2" exhaust hose back on the nipple. Let you all know how things turn out.

Just an update. Bob, I think the muffler must be painted with invisible paint, I cannot locate it where you suggest it should be. I do have this refer compressor in the way so I will have to remove all the stuff in the starboard lazarette and climb in so I can get a better look. I have a hot water heater (shaped like a cube) in front of the waste tank, plus the CNG cylinder, the battery charger, cooling system over flow bottle as well as the refer compressor in there plus all those large diameter hoses for the waste tank which all look like exhaust hoses, so it is really crowded and hard to see.

I am working with List Marine in Sausalito to replace my mixing elbow, really great folks. They suggested that if I could remove the three nuts holding the exhaust flange, and all the hoses, I could bring the whole mess over to them and they would change out the elbow for 1/2 hour labor. At this point I probably could do that myself but for 1/2 hour labor, it is not worth my time. Plus when I showed them a website for the elbow, they said the web price was much better than they could do, so they suggested I buy the part and they would still do the swap out. That saves a day's labor for a "house call" and at probably $100/hr, pretty nice.

Of course the problem is getting the 2 inch, wire reinforced hose off, that takes a gorilla. But with a chain strap wrench (attached to a vice grip) and a large pair of channel lock pliers, I was able to twist if off, getting it back on will be another matter. Let you know how this all turns out.

That cube water heater sits on an approximately 14" pedestal. The water muffler is to the left of the pedestal and at the bottom of the opening. I just replaced the W/H so I got a good view of it. The exhaust lines drop straight down to it. You might see it easier with a mirror on a wand. It is up against the head bulkhead. Working in that locker with all the angles and limited room did cause some pains in normally unused muscles. I don't think you will see the muffler without a dip down into the locker.

That sucker should go right up to 3k in neutral. but thats no indication of power production.
Couple of other suggestions. Have you actuated the throttle from the engine itself? making certain that you are not experiencing some limitation from the linkages or cable? there are locknuts on the linkage and bell crank. There is also a max throttle stop stud / nut. Rare that it would vibrate out or loose but I would check.
I assume you are looking for full revs while underway not at the dock? the boat needs to make hull speed.
Also your getting up there in engine hours @2400 HRS. For a diesel thats in constant use that would be small taters but for a marine auxiliary its getting up there. If you have a harbor freight store around (I shudder to buy tools from them) but you can purchase a diesel compression kit for cheap chicken. I would see how the compression checks out. She may run smooth but just not have the compression left in her to make the power. Does it consume any oil? any black or blue smoke on start up? or after high load and then backing down? low compression/ worn /dirty injectors typicaly black smoke. worn scraper or compression ring= oil (blue) worn valve guides (blue) when was the last time the valve clearances were checked? I have seen valve adjusts done incorrectly and that can have a serious effect on power. valve clearance check is a 15 minute procedure. typical tappet / lock stem system. Ive seen some crazy adjustments over the years people do strange things. Looked over bike for a buddy and the clearance was set to 3mm instead of .003" thats a big difference!
Getting the injectors checked out and cleaned wouldn't be bad policy either. They are simple to remove and I'm certain you can find a local shop to clean and check the spray pattern/volume for around $25-$45 per injector.

Good luck and keep us posted!
Capt. Ian

Capt Ian, all super good suggestions. UGGh lots to do. I did have the engine surveyed three years ago when I bought the boat, a super diesel mechanic spent 4 hours checking everything, at least it seemed so and costs like he did. The valves were adjusted also three years ago but according to the log book, the last time the injectors were "serviced" were about the same time the riser was replaced due to an "rpm" issue, that was 1999 at 1240 engine hours, so maybe a injector service is due now. I will check that out once the elbow has been replaced. It is on order and I have a great mechanic lined up should I need it. Oh I will also check out the cable connection at the engine, simple to do, just forgot.

Bob, I will crawl into the cavity and look again. If it is that hard to see, how in hell does one replace it? Amazed you were able to change the hot water heater. I would have to remove the refer compressor and then have it pumped and recharged, or toss it. I really like the idea of mounting the compressor just below the nav table against the forward wall of the refer. It might make some noise but sure would free up a lot of space in the lazarette.

HerbertFriedman said:

Bob, I will crawl into the cavity and look again. If it is that hard to see, how in hell does one replace it? Amazed you were able to change the hot water heater. I would have to remove the refer compressor and then have it pumped and recharged, or toss it. I really like the idea of mounting the compressor just below the nav table against the forward wall of the refer. It might make some noise but sure would free up a lot of space in the lazarette.

Click to expand...

I probably commented on reefer noise elsewhere, but our new (2016) Isotherm unit is quieter than our decade-old Frigoboat, and it was pretty quiet.
If you go with a modern fridge conversion, they are more silent than the old ones. You can can barely hear our compressor and small cooing fan at all.

add link for our fridge upgrade:
http://www.ericsonyachts.org/infoexchange/entry.php?408-New-refridgeration

Loren

It's there! Removal and replacement looks possible without removing the water heater but not a job to relish. I could not have done it before I cleaned up the nelectrical mess at the front of the locker.

I wouldn't remove and replace the refer unit. The new one would cost about the same as having the old one rehooked up and charged. My old unit drew 13 amps. The new one draws 3.5 amps. It is easy for a DIY installation. The unit under the sink is so quiet, you can't hear it run. Noise will not be a problem under the nav table.

I will look into the Isotherm unit, my refer compressor for the port refer was recharged but every so often the red "low freon" warning lite comes on. I dont know how old both compressors are but they could be original. Also, I have not measured the amperage when running but over a day without shore power, the batteries are down to about 50% SOC so the 3.5 A that Bob quotes sure sounds nice. Bob, did you install the same Isotherm unit?

Herb, I have an Isotherm GE-80 for the galley icebox. It sits under the bottom drawer in the galley sink area. I use the small locker ahead of the galley for all my tools. The GE-80 is rated at 2.5 amps. Loren has reported that his GE-80 is currently drawing between 1.7 and 1.9 amps and keeping his box at 35 degrees. I am using a GE-150 for the other box at the nav station. I'm planning to use it as a freezer so I need more cooling. Much better than the old unit that drew 13 amps. No need for that extra battery now. These units are unbelievably quiet. When the old unit acts up, toss it!

Just an update on my low RPM problem: I received the exhaust mixer elbow from Toad marine, great price and a new exhaust gasket. The diesel mechanic I am working with suggested I remove the entire exhaust with the mixer elbow attached, bring it to him and he would change out the elbow. Great that a mechanic was willing to let me buy the elbow, the price from Toad marine was cheaper than he could get it for.

Anyway after lots of cursing, skinned knuckles, I was able to loosen the 2 inch very stiff exhaust hose from the reducer fitting (that goes to the muffler) and the three nuts holding the exhaust flange onto the exhaust manifold. For 1/2 hour labor, the mechanic replaced the elbow. I tried that myself but the pipe nipple connecting the elbow to the flange was really on tight. After much PB blaster, I put the elbow in my home vice and tried to loosen the pipe nipple with a 10 inch monkey wrench, no go, I put a pipe on the wrench for extra leverage and actually broke my vice. I surrendered and brought the whole mess to the mechanic.

I was told there was lots of grunting but finally it gave and I have a new elbow, nipple attached to my old exhaust flange. The 2 inch exhaust hose was really stiff so the mechanic sold me a two foot length of new Vetus exhaust hose that was much more flexible.

Two hours later, I had the elbow, flange and hose reattached. Alas no change in the rpm, I still could not get the engine to rev up beyond 2500 rpm in neutral and 2200 rpm in gear (at the dock but even outside, no more than 2200 under weigh) Uggh, back where I started, not discouraged, the elbow was 18 years old and had 1200 engine more hours so it needed to be changed. And the education was well worth the effort.

Next thing to try is back to basics, to see if pushing the throttle lever at the engine is the problem, need the admiral's help to read the tack. If that does not help, time to call the mechanic for a boat call or I sail to the mechanic in Sausalito and Uber it home Let you all know.

Herb, have you checked the accuracy of your tach? Could be you are getting full rpm and your tach is lying.

Herbert,
I'm wondering if there was much carbon buildup in your exhaust hose and elbow? 1200 engine hours doesn't sound like that much to me.
Frank

Bob, I had the engine surveyed three years ago when I bought the boat. Then the tach in the boat read about 200 rpm lower than the surveyors tach which measured the rpm mechanically by placing a sensor against the flywheel central nut. But this low rpm is recent. If I go the route of the mechanic, he will have a tach.

Frank, I just changed out the mixing elbow and section of exhaust from the elbow to the reducing fitting which goes to the muffler. So that part is clear but certainly the muffler could b clogged. As I told Bob, I cannot even see the muffler which is just forward of the holding tank. There is a starboard refer compressor in the way, I am sure the muffler is there but getting that puppy out seems really tough.

Will let you know what I find out. Meanwhile, the engine seems to run fine, just cannot get to the 2500 rpm in gear that I used to.

I will check out the cabling shortly, as I indicated, changing out the mixer elbow had no effect.

Just thinking, does anyone know if the three diesel injectors could have this effect of limiting the rpm? Otherwise the engine runs fine.