Major Yanmar scheduled maintenance: Lessons Learned

[scross]

I'm sitting in a marina in Anacortes right now. The plan was to be in Pender Harbor leaving for Princess Louisa Inlet tomorrow.
Let me back up. A week ago we picked up our R25 Classic from a highly regarded service shop in Anacortes after getting Our Journey's 500 hour Yanmar service completed.
FIRST MISTAKE: The boat was on the trailer during the service. The shop did not take the boat out for a sea trial to make sure everything was AOK with their work before we picked it up. Since we were planning a 16 day trip immediately after picking the boat up from them this turned into a major problem.
SECOND MISTAKE: We supplied a lot of the parts for the work. The impeller we supplied, while NIB was 18 months old. Use a fresh impeller if you are having one replaced, not your older unused spare.
THIRD MISTAKE: Within 10 minutes of leaving Bellingham with the boat noticed high coolant temps (200-210 degrees) at anything over 2,300 rpm. Should have made a hard left turn to Anacortes and the shop right then even though it would have screwed up all our marina reservations for the first week of the trip.
Did call shop immediately to discuss issue. Learned that 4BY2-150 coolant temps of 195 to 205 were ok - no long term damage to engine. Shop in Anacortes thought impeller was the problem and we arranged Diesel tech in Ganges for 9 AM next morning to replace impeller with 6 month old spare #2 impeller. (What? Don't you carry 2 spares??)
FOURTH MISTAKE: Tech in Ganges was booked solid and, while he was great and fit us in, didn't have time to do sea trial to see if replacing impeller actually solved problem. You need a sea trial to make sure known problem is fixed after expensive mid-cruise emergency repair work! The newly installed impeller #2 did not solve problem.
So, we ran around the Gulf Islands for a week limiting the engine temps to 200 degrees max which meant 8 knots max speed. Gave up on PLI and seeing friends at Buccaneer Bay. Weather was perfect BTW. Noticed we had no hot water from running engine. Limped back to Anacortes from Ganges over four days stopping at great locals along the way.
In Anacortes today problem was identified and fixed in 30 minutes. We even did a sea trial to confirm the fix! They had sucked out 2.5 gallons of coolant but put back only 1.8 gallons of coolant when it showed full. Air bubbles!! Didn't "burp" the coolant properly when first serviced. Fix was to properly burp coolant and add, in our case, add more of 0.7 gallons of coolant to system.
MORAL OF STORY: If you have high coolant temps AND no/little hot water after running the engine for a couple of hours (Shore power to heat water doesn't count) immediately after replacing the coolant in your Yanmar, check to make sure you have full coolant. Remember that the amount removed should equal the amount installed!! Also it may be OK to run 4BY2-150 engine at under 205 degrees at low RPM until you can get issue fixed.
Heading back to Gulf Islands tomorrow and still having a good trip. It's just not the trip we expected!

 

[Brian B]

An 18 month old impeller that has not been used should still be pliable, they are not date stamped for freshness. I have used a two year old impeller out of the box and it is very pliable and has worked in the engine for the past season. (When you buy one how do you know when it was manufactured?) Draining anti-freeze can be tricky with the "burping". After I do mine I frequently check the engine level by removing the engine cap (when cold) and add if necessary. Checking the overflow bottle is not accurate as to the level in the engine. The tech should have informed you to keep checking the engine level and given you a jug of 50/50 anti-freeze to top off as necessary. I wonder if they completely drained the system, in order to do so the heat exchanger needs to be removed. When I read stories like this I am glad I do this routine maintenance myself even though it can be a real P.I.A. at times.

 

[NorthernFocus]

"Second mistake" was not a mistake at all. The impeller had nothing to do with your problem.

"Third mistake" was the big one. Good on you that you recognize it and sounds like have learned from it. Too many boaters let plans/schedules push them into making bad decisions on the water.

 

[scross]

Brian, you are right about not knowing the actual date of impeller mfg. I knew mine was at least 18 months old but it could have been much older. It had been stored in the boat in varying temps. Mechanic at shop checked my impeller for condition before installation and thought it felt fine. That said, when shop told about overheating they blamed my "old" impeller as the most likely cause of the problem. Ganges tech who replaced it also thought spare #1 impeller was fine. But next time I have impeller replaced I'm getting one ordered directly from Globe just before the service.
In deciding to press on to Ganges and try to save our schedule, that hour long 4 call discussion with Anacortes shop was made at Sucia which put us almost half way between Ganges and Anacortes. The high temps were stable and controllable with rpm. The Anacortes shop really thought it was an impeller problem at the time. Still, pressing on was a bad decision. Hindsight is great!

 

[captstu]

Typically, the impeller produces significant excess water flow beyond the minimum required to control the engine temperature.

I have renewed impellers with as few as 2 remaining blades - still with no signs of overheating.

If there us substantial water flow thru the exhaust or thru the sea chest if yours is clear as most rangers, than the impeller is not at fault.

Add to your pre-departure check list, "check water flowing out of exhaust or flowing thru the sea chest at first start".

Water flow thru the exhaust is independent of engine temperature - but is absolutely necessary to cool the exhaust tubing and water lift muffler.

Gauges that measure exhaust water temperature and/or sound an alarm when there is insufficient flow or excessive temperature are absolutely essential on inboard engines. It is to bad Fluid Motion doesn't fit such an indicator to all boats they built, but you should request one from your dealer - for less than $300 you should be able to protect yourself from an unknown impeller failure or a blockage (like a plastic bag) from clogging your inlet thru hull. Repairs after a failure cost 10 times or more money since the exhaust system is frequently destroyed.

 

[nzfisher]

A hard earned lesson-in most situations where a high engine temperature is encountered, opening the heater to the cabin should drop the engine temp enabling you to get to port or extending run times with more acceptable run temps. My understanding of the Yanmar BMW engine is that it is designed to run at higher temps in the autos than we ever see in our boats. If someone "in the know" could confirm this it would be great

 

[scross]

I have both the AquaAlarm flow and exhaust systems installed in Our Journey. Exhaust water temps never got high enough (200 degrees) or flow low enough to set off the alarms. I was watching the Yanmar display like a hawk the first 20 minutes of the trip until it was obvious that the coolant temps were higher than normal. Before the 500 hour service I would run 190-192 degrees at 2500 rpm and 192-194 degrees at 3000 rpm.
For the next 10 hours of engine run getting back to Anacortes I looked at the coolant temp readout about every 15 seconds or so. Not a fun way to spend 10 hours!
BTW, a retired Yanmar marine engine warranty rep told me that the non-marinized BMW Diesel when used as a generator is rated for 230-240 degrees. He thought they would be fine in our application up to 210 degrees. Everyone else I talked to during our four day adventure said to keep the temps at 205 or below.

 

[Lummisailor]

Synergy our recently purchased 2008 R25 runs at 175 degrees at 2200 rpm and goes to 210 at about 2800rpm . from what I am reading on this site it sounds like the norm. Any further info would be appreciated.

 

[scross]

Running 210 degrees is too hot at 2800 rpm. You should be where we are now at about 192-3 degrees at that rpm. Even at 3600 rpm you should not get up to 200 degrees. Have you checked the coolant level recently to make sure it's full to the cap on the top of the engine?

 

[Lummisailor]

I check the coolant before each first start for the day always up. Also have good raw water flow at exhaust. Engine has had all scheduled service by last owner including replacing impeller. engine has 2000 hrs. and had turbo, injector and filters serviced at 1800 hrs. Although I haven't tried lookin in coolant tank with at start up to see if I may have a air block thanks for the suggestion. Larry

 

[scross]

With our problem described above, the overflow coolant tank in the starboard cockpit locker was always full even though we were down 0.7 gallons of coolant. The air pocket in the coolant system had to be burped through the cap on top of the engine. I had thought that if the overflow tank was full then I was good. That's what I had been checking before each trip. Apparently that's not always good enough. I'm adding to my trip checklist, with the engine cool, to pull the coolant cap off and check to ensure full. On the R25 Classic the coolant cap is in the worst possible location - right under the aft cabin wall with only about 2" or so of clearance.

PS: The coolant overflow tank started working as it should once the coolant was burped at the cap on top of the engine and 0.7 gallons were added.

 

[knotflying]

Yep, before starting up in the morning it is good to check the coolant at the cap and the oil as well.

 

[Lummisailor]

If after running there is no coolant in recovery container, is that an indication that the engine thermostat is not opening and that may be a reason for temp. rise at higher RPM? And how do you burb cooling system ?

 

[knotflying]

Your recovery container may be empty because there was not enough coolant in the first place. Any air trapped in the exchanger works its way out through running. After changing your coolant you should check the level by opening the coolant cap on the engine. DO NOT DO THIS WHEN HOT! Make sure the engine has cooled down significantly before checking the level. You may be getting the higher temps if there is not enough coolant. Coolant should always be added directly at the cap on the engine, not the recovery tank.

 

[captstu]

I've been meaning to ask,

How do you get the heat exchanger cap off a 4BY2 in a Ranger 25? It is located exactly under the door to the cabin - I get it off with a long handled screwdriver and significant loss of finger skin and some blood.

Had some over heating (207 at 3600 rpm), so I checked the antifreeze level the next morning - full to the top. Today, I change the impeller and flush the heat exchanger.

Ideas? /Stu

 

[captstu]

How do I remove the pulley on the raw water pump to remove the pump cover.

Last time, 2 years ago, I removed the pump cover without removing the pulley - what a job. This time, I'd like to remove the pulley, but there are no lock nuts, allan screws, or similar attachments that I can find.

Hints appreciated.

Second question: The 4BY2 has about 1000 on it and the boat has been largely dry stacked. I opened the sea chest and it is growth free and clean - I suspect the heat exchanger is also. It it possible to back-flush the heat exchanger by removing the raw water pump and blasting water into the heat exchanger from the zinc opening?

I was thinking of putting a shop vac or the raw water pump opening to try to suck out the impeller pieces. Is there any hope?

Third question: The 4BY2 manual says the engine has 2 or 3 zincs. Any idea how many zincs are on the engine installed in the 2010 Ranger R25?

Thank you. /Stu