Does anyone know....

[sam am I]

Preface......I have a manual(V6,92 newer 135-225, carb), so I have somewhat of an idea and can interpolate/speculate with the best of them all day

However, Merc. never(I can't find it) comes out and says per-se, other than the fuel pump spec's(moot point), which I saw/have.....

So, has anyone ever MEASURED [or know first hand.....just the cold hard facts Ma'am,(V6,92 newer 135-225, carb)] "A" and "B" with a pressure gauge? [standard relative to atmosphere type (electronic or analog)]

And If so, do you know the values at idle and/or WOT for example? Min and Max values if you will.

Bonus question......Dynamically, there is "pulsing"(shaft rate) superimposed on those static levels above. Do you know the peak to peak(or peak) readings?

Background.......I will be instrumenting these area's and just need a good baseline to design from for the test setup.......There's no conspiracy at hand or foot.

View attachment my_image.pdf

 

[Chris1956]

Re: Does anyone know....

So you are looking for the oil pressure expected at points A and B?

Point A is the pressurized feed from the remote oil reservoir, right? There is a spec for the check valve on the oil reservoir. That should be the answer.

Point B is the metered oil to be mixed via tee into the fuel line, right? I would think the oil pressure would need to exceed the fuel pump pressure. Since the system is designed to keep the engine reservoir full, it may be the same pressure as the oil feed line.

 

[sam am I]

Re: Does anyone know....

So you are looking for the oil pressure expected at points A and B?

Yes but, sorta trying to avoid "interpreting" as I said I can do and agree with you sort of......

Point A is the pressurized feed from the remote oil reservoir, right? There is a spec for the check valve on the oil reservoir. That should be the answer.

Yes but. That check valve of 4 PSI cracking pressure is set to and installed such that to "allow air to ENTER", (not anything to escape) in the event the feed from the remote tank is blocked, thus avoiding a vacuum to be created inside the reservoir I presume. Doesn't really tell me......but it tells me in a failure more, i will have at least -4 PSI (rel atmosphere) But not quite looking for that....

Point B is the metered oil to be mixed via tee into the fuel line, right? I would think the oil pressure would need to exceed the fuel pump pressure. Since the system is designed to keep the engine reservoir full, it may be the same pressure as the oil feed line.

Well sort of.....That 2 PSI cracking pressure check valve (the "TEE") there is installed such that one side of it (the check valves' low pressure side is on input side of the fuel pump. An input to any pump is most likely more negative pressure level relative to its output.......say -4 PSI for example, and depending on the pump, flow rates due to usage, back pressure etc, etc, therefor in order to "crack open" and have oil flow for THAT check valve, a differential pressure of 2 PSI or greater across the valve must exist and therefor point "B" COULD be at least -2 PSI or greater. And of course, the oil pump itself and back pressure reflected from the fuel pump depending on fuel usage, crank case outlet, fuel tank inlet.....creates an output level that would influence this level as well...... I got lost all ready, the dynamics of it are too much for me, just need some to have actually measured it .........

Again, just looking for someone whom knows first hand. I may have to wing it which isn't an issue, just looking for a initial short cut of sorts.

 

[sam am I]

Re: Does anyone know....

FWIW and If was interested, I finally got it together enough to get some data recorded.......I'll pull more in the water at speed data hopefully in a week or so, I'll post that too.

Side project(wire nut data logger phase still) I have been working on.........I'm using these levels/values as norm limits for a microcontroller that reads/monitors a set of installed sensors in real time.

Basically, It works in parallel with merc's existing alarm system monitoring these other "normal" levels I'm gathering/compiling and will set off the existing helm alarm/beeper but with a different set of individual warnings codes when for example, the oil, fuel pressure, temp goes out of range.

Why? Extra/added(and some redundant) insurance for an older(no "guardian" in mine) sorta expensive engine i just dropped a few dollars in, less gauges to keep an eye on and no room/desire for more gauges anyway and because I could:noidea:.

 

[sam am I]

Re: Does anyone know....

For those interested, I was able to pull the last bit of data today but, on the lake at and around WOT(5K) now.






The motor being pretty much broke-in after being rebuilt(bored 0.015" over, fuel pump kit, yr old impeller, carb kits, gaskets and all) and now having ran about 30 Gals. of 50:1 pre-mixed.








http://ww1.microchip.com/downloads/e...Doc/41288F.pdf