Farymann genset oil pressure problem

[Duetto]

in general yes.

you may want to call ron on this. he may have one from entec or farrymann.

if not, it has 2 connectors, it's normally open, and i think it closes at approx 15 psi, not sure on thread.

 

[Duetto]

checked my files this may help. google it

oil switch 76575 4 N/O

 

[STB]

If that is a 76575-4, it is a 4psi switch

 

[Duetto]

you got me....that's what i have in my notes. the boat is in fl and i'm in ct so that's all i got.

 

[ggray]

checked my files this may help. google it

oil switch 76575 4 N/O

Old thread, but same issue with my Farymann, so I'll start here.

It seems from what I learned googling this part number that the N/O means normally open.

But for an oil pressure switch as opposed to a gauge, wouldn't it be normally closed? As in, when the engine is not running the switch would be closed sounding the alarm. When it builds up pressure the switch opens, silencing the alarm.

I'm trying to understand what I might need to look for since Farymann is out of the picture.

 

[Duetto]

hi,

there are switches and senders. i believe senders drive the gauges and switches control buzzers/alarms. so, the oil pressure sender is normally open until the oil pump creates enough pressure to close the contacts and "send" the signal to the gauge. switches can be no or nc depending on the application. the alarm they drive must match.

 

[ggray]

Thanks!

I am trying to call Ron as you mentioned; it is a Virginia area code, which is only a little surprizing these days. Otherwise, I might have to get both NO and NC to see which is needed.

I used to call them all sending units until I was corrected by a mechanic.

 

[twistedtree]

Thanks!

I am trying to call Ron as you mentioned; it is a Virginia area code, which is only a little surprizing these days. Otherwise, I might have to get both NO and NC to see which is needed.

I used to call them all sending units until I was corrected by a mechanic.

Is there a drawing for the rest of the circuit? It could be done with either NO or NC, depending on how the circuit is designed. Seeing the rest might make it possible to determine which you need.

 

[Duetto]

yes, like switches senders can be no/nc depending on the application. we have a farryman/entec and oil pressure switch is normally open. i might add that we don't have a gauge, just a light.

ron is tough to get ahold of, but i think he'll have what you need.

 

[ggray]

Is there a drawing for the rest of the circuit? It could be done with either NO or NC, depending on how the circuit is designed. Seeing the rest might make it possible to determine which you need.

Thanks!
I just found a wiring diagram, and both the oil pressure switch and the temperature switch are drawn "open", with a note that it is drawn as operating normally, so that's what I have.

 

[ggray]

yes, like switches senders can be no/nc depending on the application. we have a farryman/entec and oil pressure switch is normally open. i might add that we don't have a gauge, just a light.

ron is tough to get ahold of, but i think he'll have what you need.

Thanks for the confirmation!

I'll keep trying Ron. So the area code 703 is correct?

 

[Duetto]

"But for an oil pressure switch as opposed to a gauge, wouldn't it be normally closed? As in, when the engine is not running the switch would be closed sounding the alarm. When it builds up pressure the switch opens, silencing the alarm.

I'm trying to understand what I might need to look for since Farymann is out of the picture."

keep in mind the oil pressure sender is generally used as part of the fuel control system. on our entec the fuel control system works in the following way: the start sw feeds the water temp sender (nc), then to exhaust temp sender (nc) then to the oil pressure sender (no). the starter cranking drives enough oil pressure to close the oil sender which then energizes the fuel valve which also the engine to start. if water temp or exhaust temp rises above set point they open and the circuit is broken, the fuel valve is de-energized and the engine stops.

 

[Duetto]

yes 703 area code. i think reference to west palm was hearsay.

 

[ggray]

keep in mind the oil pressure sender is generally used as part of the fuel control system. on our entec the fuel control system works in the following way: the start sw feeds the water temp sender (nc), then to exhaust temp sender (nc) then to the oil pressure sender (no). the starter cranking drives enough oil pressure to close the oil sender which then energizes the fuel valve which also the engine to start. if water temp or exhaust temp rises above set point they open and the circuit is broken, the fuel valve is de-energized and the engine stops.

Thanks! Good to know.

I hadn't considered the operation of the fuel valve, which I assume dictates how these engine protection devices need to be set up.

 

[Duetto]

our entec has no gauges, just 3 lights (water temp, exhaust temp, oil pressure). in reality the senders are all about the fuel control system, which in turn also protects the engine. knowing the order of the circuit means the lights can pinpoint where problem is.

 

[ggray]

This genset is an HLF, same engine as yours but raw water cooled.

Unfortunately, one light serves the two alarm functions, oil pressure and engine temperature. The wires from those switches are joined as they enter the control panel, so I'd need to think how to separate them, and have both capable of shutting down the motor. I may install switches in these wires to see which one silences the alarm.

The alarm and shutdown happens after about 5 minutes of running, no load, so I wouldn't think it's a temperature problem. It could be that switch as well. When this first happened earlier this summer, the generator had been running under load for at least an hour before the alarm sounded.

I do appreciate your helping me think through this!

 

[Duetto]

on the entec, the light and control are 2 separate circuits. the control circuit wire just goes from the panel to temp sender to exhaust sender to oil pressure to the fuel valve. it is a fairly heavy wire maybe 14 ga. the light circuits are point to point, from the panel to sender and back. the light is wired to "far" side of the sender. this says if there is current there then the sender has closed and that light comes on.

a genset might overheat in 5 mins. i would get infra-red gun and check the head temp.

we're not on boat until nov. when i get there i can see if entec manual has any more info.

 

[ggray]

Thanks!

I've learned a lot working through this. This morning I also learned that I've been barking up the wrong tree. It is the temperature that is triggering the alarm and shut down. I removed the wires one at a time and it was the temperature lead that silenced it. I got my hands on a "laser" temp gauge and the cylinder was about 200* and higher.

Since I have great water flow out the exhaust, I plan to flush out the engine. Will be another learning experience.

Thank you for your help!

 

[ggray]

Engine flush with Barnacle Buster didn't seem to remove much of anything. I didn't think there would be much there in the first place, but figured it wouldn't hurt.

Should 210* temp of the cylinder head be high enough to cause a shutdown?

 

[Duetto]

as i recall, cyl head temp should be about 180. do you know if there is a thermostat? if so, i would take it out and see if it still shuts down. i think a carbon clogged exhaust elbow could also cause overheating. also, check the exhaust water temp and compare to salt water temp. it should be about 10-15 degrees higher.

 

[ggray]

I don't see a thermostat on it. I'm not sure if there are thermostats on raw water cooled engines (I know the Entec is FWC), at least small simple engines like this.

I'll see about removing/cleaning the exhaust elbow, although with the fairly low hours, and high rpm operation, I wouldn't think that would be an issue. But I really don't have any experience to back that up.

I'll check the exhaust water temperature. I assume if the temperature rise is less than that (with good water flow) it would be an indication that the cooling water is not getting where it's needed.

Amazon has an oil pressure switch that matches what I have (pressure parameters unknown on either), but I'm having difficulty finding a match of the temperature switch, just to fit.

 

[Duetto]

ok, couple of things. i have a farymann shop manual. i've included a blurb on thermostats. it appears they all have them. if yours looks like the manual, it will be under a cover with a hose connected to it on the rear of the cyl head, right behind the valve cover. i would find it, remove and test it before you do anything else. note the opening temp. the other thing i would think about if the thermo proves ok, would be salt plugging cooling passages to the head. i would think about running a salt-away thru cooling system.


FROM FARYMANN MANUAL

4.3.2 Open cooling water circuit with direct sea water cooling with thermostat
Fig. 12
The cooling water is also circulated here using an
impeller pump (1). The temperature of the cooling water circulating
around the cylinder and cylinder head is regulated by a thermostat
in the cylinder head. The cooling water thermostat is set to a
maximum temperature.
There are two versions of cooling water thermostats:
Cooling water thermostat for use with "salt water".
Opening temperature of the thermostat 50 °C.
Cooling water thermostat for use with "fresh water".
Opening temperature of the thermostat 70 °C.
The opening temperature prevents the separation and deposit of
salt crystals from the sea water in the cooling water area of the engine.

 

[ggray]

Thanks; that's very helpful!

I just spoke with someone Mastry steered me to and he said where to look for the thermostat (which he said could well be installed on this RWCed motor), same place as you are saying.

And I just got an email response from Ron (who had a loss in his family, the Mastry contact informed me). He said check next week as he did have parts.

So things are looking resolveable.

Thanks for your help!

 

[Duetto]

good luck, let us know how it goes.

 

[ggray]

Well, I've learned some things over the last two weeks. Problem still with me, but homing in on the solution. As you say, there is a thermostat. I should have spotted it, but the housing is so small (like the size of half a Tootsie Pop) I didn't suspect it contained a tiny thermostat.

Long story short, the thermostat was frozen closed, but that didn't matter because something is blocking the water passage inside the block/head. I poured water into the cavity where the thermostat lives, and it doesn't drain out the discharge port, at least not immediately. I assume it's dislodged clumps of rust/corrosion, as the problem--the sounding of the alarm-- was after the genset had been running maybe an hour, and I've never removed a pump impeller missing a vane. All the cooling water has been bypassing the motor, as did the barnacle buster I though I was flushing with.

Before I dismantle the motor to clean it out, I think I will try to back flush the water passage with some pressure and Barnacle Buster.

I have spoken with Ron who gave me the name and number of a dealer he supplies, but the number is disconnected, and Ron hasn't given me any more information yet. I do have a new thermostat, but it's too hot.

Thanks for your help and telling me about Ron!

 

[twistedtree]

Does raw water get pumped directly through the engine for cooling? Or is there coolant circulating in the engine, and a heat exchanger with sea water?

 

[ggray]

Yes, the raw seawater is pumped through the motor. No heat exchanger.

Not the best way to do it, but it does create a smaller package, which I needed.

 

[ggray]

An air pressure "backwash" failed to dislodge anything so I started tearing down the motor. I found the two water passages between the cylinder and the head were completely and firmly blocked.

Now I'm waiting to see if Ron has the orings that seal these two passages between the cylinder and the head. I bought some hi temp orings on Amazon but while they fit I think they may be too fat. I'm also checking with McMaster.

 

[Duetto]

couple of questions: 1) was the blockage rust or salt or a combination? 2) do you have access to fw at a dock? you may have to start thinking about regular flushing with fresh water and salt-away once in a while. is o-ring rubber or copper? either way my guess is they would compress.

 

[ggray]

It was dark brown, so mostly rust.

Yes, I think Salt Away should be the routine in the future. I installed the genset 21 years ago, and the lack of use some years is not the best way to treat it, but that's the way it's been.

It does get a flush with antifreeze each winter, but the understanding I have gained through this experience has made me wonder about the efficacy of that, at least the way I've done it several times. With the thermostat closed (as it would be when cold), no coolant (being the antifreeze) would have been drawn into the engine. I'm thinking now that it would be better to winterize the genset when it is warmed up, and I have at times in the past if an oil change had been needed. But several times I've winterized with the engine cold, so I now figure the antifreeze would not have entered the engine at all!

I've never had any freeze damage. Have I been lucky? Perhaps here on the southern Chesapeake it hasn't gotten cold enough long enough to freeze. Inside its cocoon, inside the engine room, perhaps it is shielded enough from the cold. But...and here is the my full disclosure: my attraction to trawlers caused me to join your forum several years ago, but I don't own one! I own a sail catamaran! The engines and the genset are set back in the sterns, isolated from whatever little warmth is in the cabin and mostly above the waterline.

Of the several forums I'm a member of, yours was the only one that had a thread relative to my problem. I hope you guys don't mind my barging in!

The other question; the orings are rubber, and the old ones have been rather flattened. But there seems to be less material there than with what I bought (16mm OD, 10mm ID). I have only the cylinder with me now, and there is no recess in the surface around the tubes that make up the water passages , so I will need to check the head to see if there is a recess in it. Maybe Ron can provide orings certain to fit.

This has certainly been a learning experience for me! Next will be finding out how difficult it will be to get the piston and rings back into the cylinder.