Potential gas in engine oil / oil sending unit / thermostat

[keith_james]

I have a 1998 Four Winns Horizon 200. It is a 4.3 Gi Volvo Penta engine. Last week, the oil pressure started moving erratically and eventually dropped to low. The temperature gauge also dropped to low. Once the oil pressure gauge hit low, the oil engine light came on and the alarm started chirping repeatedly. I checked the oil and it seemed fine. The engine wasn?t overly hot. I managed to get back in and put my boat on the trailer. I replaced the thermostat and there were some rocks in it causing it to stay open so I thought maybe there might be some correlation with the engine constantly running cold and the oil pressure. I put the boat in the water, turned over the engine, and ran it on idle for 20 minutes with periodic times of throttling the engine. Temperature and oil pressure gauges were working and seemed to be reading correctly. I put the boat in the water the next day, to try running it around and after about 20 minutes, the exact issue happened again. The oil pressure went down low, temperature went down to low, oil light went on and the alarm started chirping repeatedly again. I checked oil and everything seemed to be fine. When I did run the boat on the lake for about 20 minutes I did notice some degradation in performance. I was running at 3000 RPMs as I normally do, however, I was not getting quite the same speed. I got home and decided to replace the oil sending unit. I am currently waiting on that part. In the meantime I hooked up a manual oil pressure gauge to the engine, put the ear muffs on, and started the engine. No temperature readings but I was getting around 48 PSI during idle and about 61 PSI when I throttled up. So I am hoping that the new oil pressure sending unit will fix this issue. Or it may be that the VDO dash cluster has gone bad. When I was performing the test with the ear muffs on, I started smelling a little more gas. I shut down and checked the oil. I am pretty sure I am smelling gas on the oil dipstick. Also, I believe, the oil level on the dipstick is a little higher than what it previously was. Not sure where to go from here. All the marina?s in the area are backed up 3-4 weeks with work so I am trying some self-diagnosis. I am fairly new to boating, but thinking gas in the oil is not good. Does anyone have any recommendations in terms of what to look at next and/or how to verify there is gas in the oil? What other symptoms could be causing this to occur? Any help is greatly appreciated.