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Post by my3girls on Apr 19, 2015 17:49:08 GMT -6
Hello, I just had my 97 sea pro 210 w/a with a 4.3 vortex mercruiser motor rebuilt last week, here is my problem !! Oil psi is at 8psi at start up cold, I give it throttle and goes up to 30-40 psi. As motor gets hotter oil psi drops and alarm will go off !!! Still has fresh, clean oil in it from the rebuild I replaced the gauge & oil pressure sending unit. Merc manual says " min 4 psi" at idle, I believe oil pump is working ok because the pressure goes up and down when I throttle up and down. I got the correct gauge, 80 psi. Mechanic is taking boat back to look at it. Any ideas what it could be  Thanks for any advice |
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Post by Juan on Apr 19, 2015 18:50:17 GMT -6
I'm no mechanic but have rebuilt a couple of car engines... Is it smoking any? Were the cylinders bored? Do you know what kind of compression you have on the cylinders? If the cylinders walls were bored, you will have over sized rings and if not, they should have been ground to break the glaze made by the old piston rings...either way, it usually takes a few miles after a rebuild for the rings to seat properly and until then, the oil pressure won't be what it should be.
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Post by my3girls on Apr 20, 2015 1:58:03 GMT -6
No smoke, not sure about the other stuff. He said to change oil after 15 hours. Im gonna run it for a while then do oil change with the recommended merc oil & filter
Thanks for the help !
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Post by freezerfiller on Apr 20, 2015 7:05:52 GMT -6
That doesn't sound good. Definitely take it back to the mechanic. Could be a number of things, spun bearing, bad pump, etc
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Post by my3girls on Apr 20, 2015 11:03:11 GMT -6
Yes, on the way back this week, thanks for all your help !!
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Post by my3girls on Apr 21, 2015 6:05:37 GMT -6
Curious, i replaced the oil psi gauge and the oil pressure sender, is there another oil pressure sender/solenoid/switch that would cause the gauge to read low psi ?
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Post by freezerfiller on Apr 21, 2015 10:36:44 GMT -6
Ahhh, so we have some new information.... you need to make sure you have the right sending unit for the gauge that you have or it can read wrong.
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Post by my3girls on Apr 21, 2015 12:11:01 GMT -6
Im pretty surw there a match, its a 80psi gauge and i told them its a 4.3 merc with an 80 psi gauge.
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Post by freezerfiller on Apr 22, 2015 5:57:33 GMT -6
Most boat gauges are electric, and read the resistance (ohms) from the sending unit. If the Ohm range of the sending unit doesn't match the gauge, it could be off significantly.
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Post by my3girls on Apr 22, 2015 13:27:50 GMT -6
Do you no the ohm range its suppose to be?
It is a 80 psi gauge
4.3 mercruiser vortex I/O
Thanks for all help and info !!
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Post by freezerfiller on Apr 23, 2015 9:52:48 GMT -6
Nope, but if you know the model # the manufacturer should have the ohm range on their specs. Problem is, you don't know what the sending unit is rated for.
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Post by my3girls on Apr 23, 2015 16:17:29 GMT -6
Engine model # ?
When I turn the key to the on position, alarm will sound telling me its working them goes off. The alarm im hearing is small/light sounding chirps not like the one when I turn the key on, do you no what that chirping sound is ? If I bring throttle up a little it stops chirping.
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Post by Juan on Apr 23, 2015 17:42:03 GMT -6
This may be a stupid question but have you checked your oil level? Low oil can cause low oil pressure.. and as your engine heats up, the oil does too and becomes thinner, thus dropping oil pressure as the engine warms up... What pressure is your oil pressure gauge showing when the alarm goes off?
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Post by my3girls on Apr 24, 2015 2:04:36 GMT -6
Yes, the oil level is around a 1/2 quart to high, , mechanic said to change the break in oil after 15 hrs and use the recommended oil from mercruiser/quicksilver 25-40 (thats what I use in it anyway) the mechanic said it takes 5 quarts, mercruiser says 4 1/2 quarts, maybe because of the filter? The alarm , a faint sounding chirp will go off around 8-9 psi.
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Post by Juan on Apr 24, 2015 7:02:08 GMT -6
A quick search looks like at 2000 rpm, the 4.3 oil pressure should be between 30-70 psi.. If you suspect the sending unit or gauge is bad, you could remove the sending unit and check the pressure with a mechanical gauge but based on what you've done, I'd take it back to the mechanic... sounds to me like something isn't right with the rebuild.
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Post by my3girls on Apr 24, 2015 13:40:14 GMT -6
Yes it does go up to 45 psi at 2000 rpm and stays there no problem, my issue is at idle in neutral. Mercruiser says 4psi, at idle in neutral, that sounds low to me, im putting a mechanical gauge on jt in the morning, eitherway its going back to mechanic.
Thanks for all your help, ill keep you posted on what happens !!!
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Post by freezerfiller on Apr 24, 2015 21:51:04 GMT -6
I agree, you should have at least 30 psi. Let us know what the mech gauge says. I suspect it will read similar results. If the electric constantly read low, I'd think otherwise, but who knows?
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