Velvet drive 71C oil pressure

[GILow]

Hi Cruisers,

My guardian angel is due a pay rise. This afternoon, while testing the engine after a cooling system rebuild, the return oil line on the transmission cooler blew. The reason I love my guardian angel is because there are a hell of a lot of worse places to lose your transmission oil pressure than in the pen with the boat tied up at 6 different points.

So, now that I have finished thanking my guardian angel, I will buy some new oil lines AND deal with the problem that the transmission oil pressure gauge has not worked for a very long time. Such a long time that I have actually forgotten what a "normal" pressure reading is.

The current gauge has a scale of up to 400 psi (27 bar). The sender unit is dead, having been bathed for many years in salt water that leaked from the old engine driven refrigeration system. (now removed and sent to the scrap metal recycler)

I went looking for a 400 psi sender and I am not totally surprised that I can get a brand new sender AND gauge that reads up to 200 psi for less than half the price of a new 400 psi sender.

Checking the workshop manual for the 71C is a bit cryptic, there is a reference to needing a gauge that reads EITHER to 200 psi OR 300 psi.

Other service manuals and online web searching reveal pressures in the range of 80 to 160 psi as normal, depending on whether you are in reverse, forward or neutral.

I seem to remember reasonably low readings on the gauge for the short time it worked, but I would be very interested to hear from anyone about their observed pressure readings. If the majority are seeing sub 200 psi readings then I think I will take the minor risk of buying the new sender and gauge combo with the 200 psi range.

Matt

[bletso]

Your transmission had a pressure gauge? Uhm.... Anyway, I have service and shop manuals here Manuals | Sailing Vessel Vigah The bottom velvet drive link page 38 lists all the pressures. It is also the most complete manual

[GILow]

Thank you Bletso.


Yes, that's the manual I am working from already, but I do appreciate the link.


You are right, the inclusion of a pressure gauge is a bit weird, and I would not bother with it (I have not missed it for the last couple of years) except for the fact that there is a space for it on the engine control panel. I reckon it is kind of redundant, by the time it shows anything important it is probably too late anyway. I don't really want to spend lots of money making it work again for no real gain, but a dead gauge on the panel sort of makes me feel uncomfortable.


Those pressures tell me a 200 psi gauge is adequate, so unless someone has observed higher pressures I think I will risk the new gauge and sender combo.


Actually, I would probably be more likely to find someone with a pressure gauge on a water ski boat forum, the velvet drive is pretty popular here in Aus with the lower HP inboard water ski crowd. But I am not THAT desperate.


:^)


Thanks again,


Matt