OK to cruise the canal?

[garbageguy]

My 1998 Wellcraft 240SE's VP 5.7 GL runs great, but has low oil pressure. It has a VP SX-M 1.60 outdrive. It is my second season with this boat, it has a couple electrical gremlins, but runs very well. Oil pressure gauge reads about 40+ psi when cruising, but can be 20 or less when at idle or very low speed, especially after running a bit (and sometimes can hear a little lifter tick at that time). Temp gauge reads consistently just above 160 when warmed up. I don't know how many hours are on the engine, and don't have previous service records. From all indications, this boat was used regularly and probably maintained pretty well. I suspect it has a lot of hours and I plan to dig into the engine a bit after taking it out this season. It needs oil regularly (about 1 quart per 5 or 6 hours run time), but there is no obvious site or smell of burning oil, none in the bilge or water, none in the engine oil, not sure where it's going.

The Admiral wants to cruise the canal this fall, but I am concerned about the low oil pressure at low speeds for extended periods of time. Should I be concerned about that? Any idea where the oil is going? Any suggestions for what to do to it when it comes out this season?

All thoughts appreciated.

 

[Maclin]

Re: OK to cruise the canal?

What do the spark plugs look like? They would show some oil burning if the oil is getting past the rings into the combustion chamber at the rate you describe.

What viscosity of oil do you use? How often is the oil and filter changed?

There could be an oil cooler in your system, though I doubt it, but a leaky one fits some of your symptoms. If there is one it can leak oil into the raw water supply, and also cause lower than normal oil pressure if it is a severe enough leak. But you would be able to see evidence of that leak in the raw water output.

If you do not have an operator's manual or other manual for your setup, try searching at the VP site, link below. You would need t know your full model number which should be on a tag on the flame arrestor cover on a model that new.

Publication search - Publication Search : Volvo Penta

 

[alldodge]

Re: OK to cruise the canal?

My 1998 Wellcraft 240SE's VP 5.7 GL runs great, but has low oil pressure. It has a VP SX-M 1.60 outdrive. It is my second season with this boat, it has a couple electrical gremlins, but runs very well. Oil pressure gauge reads about 40+ psi when cruising, but can be 20 or less when at idle or very low speed, especially after running a bit (and sometimes can hear a little lifter tick at that time). Temp gauge reads consistently just above 160 when warmed up. I don't know how many hours are on the engine, and don't have previous service records. From all indications, this boat was used regularly and probably maintained pretty well. I suspect it has a lot of hours and I plan to dig into the engine a bit after taking it out this season. It needs oil regularly (about 1 quart per 5 or 6 hours run time), but there is no obvious site or smell of burning oil, none in the bilge or water, none in the engine oil, not sure where it's going.

The Admiral wants to cruise the canal this fall, but I am concerned about the low oil pressure at low speeds for extended periods of time. Should I be concerned about that? Any idea where the oil is going? Any suggestions for what to do to it when it comes out this season?

All thoughts appreciated.

Your oil pressure appears to be normal. The rule of thumb is 10 punds per 1000 rpm and running under 20 after running on plane for a while is normal. My 502 and 454 do the same thing. Merc indicates in there manual 5 psi is ok at idle, and I don't like that my self, but it is what it is. The gauges on boats are also known to not be very accurate, but they do provide a good visual of what the norm is. If you want to make sure it's not getting to low put a hand deld mechanical gauge on it wher your electrical one is currently connected.

Since your not seeing any oil your burning it as the engine runs. A little oil is getting past the piston rings or valve guides and is burned in the combustion chamber. Long periods of idling can cause carbon to build up on your plugs and can fowl out. Frequesnt higher rpm runs will help keep most of it burned off. If you do a compression test this will provide you with the current state of your engine. If your compression is in good shape then it's prbably valve guide seals, if your compression is low on some cylinders, squart some oil in the cylinders and do again. If compression comes up doing a wet compression test then it is the rings, if not probably valves.

If you choose to do the canal run, bring along some new spark plugs and tools just in case, or at least tools and wire brush to clean the plugs. You will know more after testing.
Good luck