M35B Hisssss

[Ron Hill]

Ken : The ONLY auto drivers (other than race car drivers) that I've ever met that look at auto oil pressure gages PERIODICALLY are people that are also PILOTS and are use to cross checking the engine / flight instruments every couple of minutes !!

My thoughts!!!

[KWKloeber]

Ken : The ONLY auto drivers (other than race car drivers) that I've ever met that look at auto oil pressure gages PERIODICALLY are people that are also PILOTS and are use to cross checking the engine / flight instruments every couple of minutes !!

Ron,
I believe that you are missing the point of having any gauge (oil, temp, or voltage) IN ADDITION TO an alarm.  A gauge is NOT intended to replace an alarm for a sudden failure.

I would bet that 99% of owners look at the panel when they start up/shut down or leave the dock and will look at voltage, fuel, temp, AND oil pressure.   So if engine temp is creeping upward due to a Hx obstruction (or pick another cause) one can observe that over time; i.e., BEFORE an alarm sounds.   If the oil pump is going bad one can also determine that over time; i.e., BEFORE the alarm sounds.

The same argument you use against an oil gauge can, by extension, also apply to a temp gauge or a voltmeter on the panel/at the Nav.  You do not observe them 100% of the time, so they have no value, correct?  However, when you do observe a gauge (including oil) it can provide good information as to overall health and especially a trend.

The two instances of oil failures in autos were not to say that having a gauge would make any difference in those two circumstances -- just pointing out, from my own experience, that oil circulation systems are not as failure-proof as you had claimed they are.

[KWKloeber]

Aaron

KUDOS! (w/ fingers crossed)

As an option, a diesel truck shop can test/rebuild injectors for a fraction of the cost.

I am not familiar with stuck heat shields - maybe talk with your Kubota dealer mechanic?

-Ken

My game of Whack A Mole seems to have paid off. Installed the new relief valve, and the hissing seems to have stopped! Fingers crossed it does not return, and that the valve really was the issue. The old spring was definitely a fair bit softer than the new spring. Also the ends of the spring were pretty worn looking. We also cut apart the oil filter, and there no signs of metal flakes in it, so I'm feeling pretty good about the state of internal bearings.

Unfortunately, now that the engine isn't hissing, it's become very evident that two of my injectors are super noisy. They do have a fair bit of diesel wetness around them as well, which I've been aware of for a couple seasons. I'm thinking the injectors are likely the cause of our engine bogging, and poor fuel consumption this season. One of them especially is hammering away compared to the others. So I ordered new injectors from Kubota and attempted to install them today. I hit a roadblock though. I can't for the life of me get the old "heat shields" out. I've tried mechanics pics, PB Blaster, gentle tapping with a hammer and drift. Nothing is budging them. All four are stuck. I didn't find any tips in the tech notes, or the forum, and it seems that the M25 doesn't have this part? The service manual suggests jamming a Philips screwdriver in to try to pull them out, but I'm hesitant to do anything that could create metal debris.

[Craig Illman]

Ken - Maybe he is talking about the copper compression washers between the injectors and the engine head?

Craig

[Ron Hill]

Ken : You are right AGAIN!! 

I see the light - just didn't realize that the closed engine oil system (even with routine maintenance) is as problematic and the engine temperature cooling system with it high probability of intake clogging, impeller failure and heat exchanger problems!!

"Out" here!!   

[KWKloeber]

Ken - Maybe he is talking about the copper compression washers between the injectors and the engine head?

Craig

Craig
No the B engines have metal, cup-shaped, heat deflectors that sit in the recess around the base of each injector.  I just haven't known of anyone (yet) who had to deal with them.

[Sailing Amok]

Bringing this thread back from the dead, incase any one else comes across either of these issues.
Re the hiss: After a full season of sailing, I am confident that the oil filter assembly pressure relief valve was the culprit. The hiss has not returned.
Re the stuck injector heat deflectors: My Kubota dealer said just reuse them if I can't get them off. Well, things were good for maybe 20hours of motoring, and then the injectors started to sound off again. The 2023 season was just about over, so I left them to deal with until the winter layup. When I pulled the (new) injectors, they were black. Looked like they'd been in there for years. Had a friend who's a heavy equipment mechanic come by with a slide hammer, and it popped the cups out with little issue. Only the aft most cylinder posed an access problem for the slide hammer, but with removal of the aft cabin access cabinet, the slide hammer was able to fit. I put the old but rebuilt injectors in, and had no issues for the entire 2024 season. I had the new but filthy injectors serviced, and now cary them as spares. So, if anyone has an issue with stuck injector heat shields in a B series engine, do not try to reuse them. Get a slide hammer, and it's a two banana job.

[Ron Hill]

Guys : If you think the hssss/noise is coming from the raw water pump - REMOVE the belt and run the engine for a minute or two. It will not hurt the engine not to have raw water for a short period of time!!!

A thought