Originally Posted by westpole
Sort of new at this boat diesel
thing and was hoping for an opinion or two.
I have a 1981 vintage Perkins
. It starts every time instantly. It blows a cloud of smoke but after two to three minutes no load 1500rpm most all of the smoke goes away and just a perceptible amounts remains. My oil
pressure shows 35lbs at 2000rpm, 20lbs at fast idle but only 5lbs at slow idle. The water
temp will climb to 200F when cruising at 90% throttle for any length of time but stays around 180 at 3/4 throttle.
Any thing unusual in these observations?
YES. That is too low oil
Do as others have advised and attach a mechanical direct reading oil pressure gauge. If it reads the same, you have a problem.
What weight/viscosity oil are you using? If the water
temperature you are motoring in is over 70 degrees F., you should be using 40weight CD rated oil.
I recently rebuilt a 4.108 for a customer whose fuel
transfer pump was leaking diesel fuel
into the crankcase. It thinned the lube oil until a connecting rod went through the case. He admitted to checking his oil and it was always up, he was checking diesel fuel in the oil, which does not lubricate the engine
properly. Cost him $6,000USD
So, if you are not "making oil" and your oil pressure is that low, it may be time for a rebuild
; new bearings, seals
, gaskets, rings and a thorough check of the oil pump, piston rings, cam, crankshaft, cylinder liners, etc.
Good luck and keep the dry side up.
Tom - Love those Perkins