T&T: Fluctuating oil pressure guage on Ford-Lehman 135

[Bob McLeran]

After checking the engine and transmission oil on Sanderling this 
morning, we got underway from our overnight anchorage off the Potomac 
River. After about 1/2 an hour, while running at cruising rpm (1600) the 
topside oil pressure gage started rapidly fluctuating +/- 15 psi from 
it's normal 45 psi (I think those gages read psi). The inside gage was 
doing the same, so assume the fluctuation was coming from the sending 
line caused either by the oil pump or the sending unit or something else.

There were no indications of any oil leaks (or any other leaks) around 
the engine, no strange smells, no unusual noises. The engine seemed to 
be operating normally.

When I checked the oil this morning it was just about 1 quart low; I 
didn't add a quart because it normally reads a little low.

When I varied the engine rpm to 1400, the fluctuations stopped for a 
short while then started again, but not as variable. At 1800 rpm the 
fluctuations were more exaggerated than at 1600 rpm. After about an hour 
it quieted down to normal, then started up again about four hours later, 
then stopped again.

After we took a mooring in Solomons and after the engine had been idling 
for 10 minutes or so, I revved it up to 1800 and it started fluctuating 
again.

Any ideas about what might be causing both gages to rapidly oscillate 
like this?

-- 
<><><><><><><><><><><><>Mozilla Thunderbird<><><><><><><><><><>
Bob McLeran and Judy Young                  Manatee Cove Marina
MV Sanderling                               Patrick Air Force Base
DeFever 41 Trawler                          Melbourne, Florida