1996 dt140 operating temperature

[kidwkr]

hi, ive been having a problem for a little while where the boat would run well all across rpms and then unexpectedly and very randomly the rev limiter and temp light would come on. I could then throttle down for a second or two and be on my way. The boat would run between 140-160f and then just above 160 before rev limiter and temp light came on.
i changed thero, water pump and temp senser to no avail.
However, i decided to change the t-stats again because i was uncomfortable with mechanic who initially changed it. I noticed that the 42c thermostat that i oredered from browns marina was a tab bit smaller than the one that was put on.
ultimately, i took the boat out yesterday and actually thought my temp gauge was broken, the boat ran at approx 120f the entire day. the motor seem to stay cooler than ever and the pee stream was strong and warm. My question is.....does 120 seem to be a normal operating temp and should the temp light fluctuate at all?? thanks so much

[findre]

I have a 1997 dt140 and had a similar problem when I bought it last year. Here is a scary possibility. Is the motor oiling? Make sure the check valve from the oil pump is not stuck preventing the motor from getting oil. The filter/flow screen will also get plugged with stuff. It will overheat the engine from lack of oil. This was intermittent, as it would oil, then not oil. I mixed till I figured why no oil was coming from the pump supply to the vapor bowl (mine is EFI).
DT140's have pretty high compression, 140psi oem, and they build up a lot of heat.
I bought motor with low compression and saw that the cylinder side looked heated. I pulled my heads, decked them, reassembled and now that the compression is at 135, the water coming out of the head is pretty very hot to the touch. I say 130 to 140.