Symptoms of overfull oil?

[HotKetchup]

I have a 1988 Seaswirl Spyder with a fresh rebuilt 350 OMC. (5.7L) 14.5 x 19 prop. 2 bbl carb. All pretty much stock.
It starts and runs good, but recently I noticed the oil pressure being very high - almost to 80PSI. The needle is very shaky(all over the guage) when at idle so I assumed it was an indication problem. TOday I noticed quite a bit of smoke coming from the crankcase vent tubes that are routed into the flame arrestor. Never seen quite that much vent smoke on any engine, car or boat, I checked the oil and noticed the dipstick was reading about 1/4" above the full mark- could that be the problem? Also after cruising for a bit, when brought back to idle, the temp rises to about 200 until I rev it a little to bring it back down then it stays down. Weird stuff....
ANd along with that, I know my WOT RPM's are low..I can only squeeze about 4100 RPM at WOT. Ive gathered from reading on here that I should be seeing 4800 to 5000.

Any Ideas...besides "drain some oil and try it out"...I plan on that...just getting other opinions in case theres other issues.

Oh and no, I didnt service the oil last time, Its still clean and new from the guy that I bought it from. He told me it was synthetic.. So Im not sure exactly how much was put in it. Just the reading on the dipstick is all I have to go by right now.

Lotta info here...sorry so long.. thanks

 

[Don S]

Re: Symptoms of overfull oil?

Over full oil will not cause high oil pressure. Actually, you would get just the opposite. If over full, the crankshaft will aireate the oil and cause lifters to rattle a little and the oil pressure may be low. Air compresses, oil doesn't.

If you are concerned about the 1/4" over full, all you have to do is drain some out. Then give it another try and see if your problems are still there. Works better than discussing it.

 

[Lyle29464]

Re: Symptoms of overfull oil?

I woul ask the PO if he put a high volume oil pump in it. They dont work out some times.

as for the prop I would need to know more about the boat to guess at the correct size. weight length

oops 60 seconds late again. sorry

 

[smokeonthewater]

Re: Symptoms of overfull oil?

fresh rebuilt engine plus synthetic oil equals blowby

the "smoke" you mention is blowby. You are getting that because your rings aren't seating. You need to lose the synthetic oil and put in some regular old cheap dinosaur based oil.... run it for a day or so and change it again.... run that until you would normally change oil.... I personally wouldn't run synthetic at all in a boat but would just change it more often.... at a minimum get the rings seated before switching to it. After that it's your money and your choice

(folks this was just my opinion.... lets not turn the op's thread into another oil debate )

next, the oil pressure is a completely different issue.... 80 psi at idle is extreme but 80 at high rpm's would be fine.... high volume oil pump on a boat engine is generally a bad idea...

The 1/4" over full is NOT a problem.... not even a little bit.....

 

[HotKetchup]

Re: Symptoms of overfull oil?

Thanks...Ill change the oil, filter etc, and see what happens.

 

[Cpt D]

Re: Symptoms of overfull oil?

Also after cruising for a bit, when brought back to idle, the temp rises to about 200 until I rev it a little to bring it back down then it stays down. Weird stuff....


Better change your impeller while you're changing the oil.

 

[paultjohnson]

Re: Symptoms of overfull oil?

excellant point by Smokeonthewater about synthetic oil and new engines. Synthetic oil is SO slippery that your engine, actually the piston rings against your cylinder walls in this case, doesnt get that minute ,tiny bit of friction required to break-in, or properly seat the rings. If you keep running your new or rebuilt engine with synthetic oil you may never get your engine broke in properly and it will be a smoker -oil user for life. As SOTW said put reg dino **** oil in and run it, maybe even for thi rest of the season to ensure a good break in, then switch back to synthetic

 

[Todd157k]

Re: Symptoms of overfull oil?

ANd along with that, I know my WOT RPM's are low..I can only squeeze about 4100 RPM at WOT. Ive gathered from reading on here that I should be seeing 4800 to 5000.

With that much blowby, you're running pig rich.. which is a loss of HP. Same problem/different symptom.