There may or may not be better oils to run depends alot on opinion, merc recos 40 wt straight or 25w40 or 30wt straight if you boat in cold water like lake superior. Oil type weight is not the problem tho imo. If I remember right you are still running your old props which are probably light on pitch and so @3100 this engine should not be breaking a sweat even and oil preasure should be up there 40 or 50. You may wanna look at some of the oil type, syn vs dino oil brand threads etc and take what you will from them, everyone has a favourite oil and reason why, but this is probably not reason why your seeing 20psi at 3100.

you get 50 psi at start so pump is prob ok
did it repeat, in other words did preasure return to 40/50 after idleing back to dock or shut/cool down
preasure slowly going down is usually heat or a filter slowly clogging up.

get the builder involved for reason in prev post, he can't blame you.

p.s. the reason for oils like 10-40 is for autos that have to start in temps like 0-20 degrees, boat engines seldom see less than 60-70 degrees and so straight 40 is mercs 1st recomendation 25W40 there #2 choice

Okay
After engines cooled down a bit yes the oil PSI went back up
docked, ate lunch and got back on fired up and back to 50 again
after running for about 10 minutes it was back to 20 again
New oil filter, new oil cooler, new sea water pump and new engine.
So my gut reaction was oil pump was okay as well but still nerve wracking none the less while your out there and underway.
I cant think that parts would fail right out of the box but with this whole project, Nothing will suprise me especially if you have been following this whole thing from square one.
Im getting pretty good water flow through engine cause my top riser to tstat housing hoses are clear and you can see the water flowing to the riser pretty well.
Now on that engine I have the newer style riser so I had to relocate the oil filter
Right now it sits off of one bolt on the riser on the side where the starboard engines oil filter sits bolted to the stringer in front of the alternator
The one where the oil filter goes to riser (port) is having the low oil pressure problem.
Any other suggestions?
Gravity too much for oil to get up there?
Lines are not kinked or tweaked but do go UP sharply to oil filter since it sits back further than it used to and lines are bent more and not straight
Possible?
Jason

kinked line , maybe, use metal fittings/tube for 90 deg bends where possible
gravity, no

to me the flag here is heat because it gets better when cools down, would be good if you knew the oil temps but find the problem, detonation, lean, etc before its a bigger problem don't experiment to may of those hot 20 min runs and problem will find you. @ 3100 the engine/oil should kewl unless your running a 30P 20"dia prop ( loading the krap out of it) which your not

Right now i still have the stocker 21 P props on there
Friend just told me that the engine may be loading up and to back out the 2 set screws air/fuel another half turn and see how that does with the PUFF out the carbs
Ill try that next weekend.
Oh man it just felt so good to finally get this thing out there.
Wife had a great time and want to keep getting her to have a great time.
She said to me last night, to sell this thing and buy BumpinUglies 33 fountain
She is in love with that thing
Jason

visc. and pour rate are TWO different things! the 20w-50. 20w means it's a 20 weight in the winter. 50 under normal conditions. additives do this...pour rate is something else...yes losts opinions out there...6 years ago we ran a 250k oil study using the current products out there....there are some new ones now that we did not test....remember lots of oil company stickers out there...few production facilities :rolleyes: i personally blend my oil for the application....good luck boys and girls.


O...did ya now???...most wear at start up is not from lack of oil:eek: ....it's from a huge tpm delta in cumbustion chamber and also the exhaust header...

what oil tmps are you running????

Dont have an oil temp gague
Just oil PSI and engine temp (145-160 degrees)
Jason

BAD idea dude! get one like yesterday. you may have too much valve spring for that application???how knows? i didn't build it. valve springs generate ASS loads of heat! HP is not free! ...your h2o will stay the same when your oil tpms could be going off the charts?? again who knows....again you need more data.

" 20w means it's a 20 weight in the winter"

no 20W means it has the viscosity of a thin 20 weight oil at 100 degrees the 50 means it doesn't thin out to more than the viscosity of a 50 weight oi at 200 degrees. This is oil temp in the engine does not matter if snow is on ground or if its 100 degrees and humid out.

Reason to use a multigrade like 5W30 in winter is so that the oil is as thin as a 5 grade @ 100 degress, a straight weight 30 or 40 is like fudge at 0 degrees F

for the record I have used the following oils and between idle and say 3500 rpm I see little dif in oil preasure and temp, at wot 5200 the 50 weight multi's run about 3-4 psi more and 5-10 degrees cooler but under light/medium loads very little difference even with choclate milk

Merc 25W40
Quaker State 20W50
Mobil 1 15W50
Shell Racing 20W50
Valvoline 10W40
Valvoline 40 straight weight

Chocolate milk ( a nice mix of 1 gallon of water and 7-8 quarts of merc 25W40) oil preasure was still just fine with this stuff

Store brand no name 10W40 ( the really cheap stuff used to flush out chocolate milk during the refill run 1 min drain and repeat process)

So okay if I get straight 40 weight oil and drain out the castrol 10W40 and fill it up with the straight 40 and it does the same thing? Then what?
Or just being like syrup it wont do it?
Man this thing is driving me crazy but yesterday made it all worth the pain and headaches and backaches and busted knuckles and tool tossing that I have gone through.
That fountain is looking more yummy by the minute
Jason