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View Full Version : 1978 S&S puked oil and pressure dropped


Mike Ingram
07-25-2012, 11:18 AM
Hi. Just bought 1978 S&S and previous owner said it had sat. He ran it with old oil and filter etc. ran fine but ran rough then he added seafoam. Ran again and oil pressure dropped and he shut down. He had run it at mechanics and pressure was 25-40. I'm going to change all flushes run it and repeat.

Any suggestions on what may have happened. I wondered about pcv as well. Any help would be great.

Mike

thatsmrmastercraft
07-25-2012, 11:35 AM
Is there any water in the oil? Save the drain oil in a milk jug to see if any water is present.

mayo93prostar
07-25-2012, 11:38 AM
where did he add seafoam, to the oil or to the gas?
if in the gas, it may have loosened some dirt in the tank or filter or carb causing it to run rough. if in oil, not sure whats up. pics....

Mike Ingram
07-25-2012, 02:34 PM
hey
seafoam in the gas. I was thinking the old oil sludge clogged the filter or screen for a bit. dont know. Im going to change oil and trans fluid, plugs, and see how it goes

mayo93prostar
07-25-2012, 03:18 PM
it sounds like you need to go through all the things that make it run starting with the list you have but include cap, rotor, wires, plugs. You may need to clean or rebuild the carburator dependion on how long it sat and if any stabilizer in fuel. I bet cap and rotor have moisture or corrosion. I would start with plugs, cap, rotor, wires. fresh gas, fuel filters, etc.

Mike Ingram
07-25-2012, 03:57 PM
thanks for the reply. I have run it in the yard a little to check the pressure and prior to buying it this week. thought it was weird that it lost 2 quarts of oil all of a sudden then when added back, no leaks. Cranks right up though

thatsmrmastercraft
07-25-2012, 04:07 PM
thanks for the reply. I have run it in the yard a little to check the pressure and prior to buying it this week. thought it was weird that it lost 2 quarts of oil all of a sudden then when added back, no leaks. Cranks right up though

Wait........now I'm confused. How long did it take to lose 2 quarts of oil? If it was burning it there would have been a heck of a cloud of smoke. Is there oil in the bilge?

Mike Ingram
07-25-2012, 04:13 PM
there was. PO ran it after purchasing for an evening. no problems. ran a little rough, put seafoam in the gas, ran it again a few week or so later. idled out in no wake zone, nailed it, lost oil pressure and oil. topped of oil and took it marina mechanic, he couldnt get pressure to drop and suggested a new oil pump???

Mike Ingram
07-25-2012, 04:14 PM
Im wondering about the nasty oil and the old filter. Wonder if it clogged the screen or filter failed.

thatsmrmastercraft
07-25-2012, 04:19 PM
I would throw some cheap oil in it, run it in the driveway for 15 minutes, then put some good oil in it and see what happens.

Mike Ingram
07-26-2012, 11:15 PM
Guys. Thanks for all the guidance. Took the boat to the lake here in Raleigh nc today and put it in. Warmed up and just as the po said. Oil pressure dropped to 0 if Ron's were less than 2000. The hotter the engine got the lower the fast oil pressure got. None at idle. Sat in the lake baffled because it didn't sound like a motor that was starving for oil in the top end.

Thought I'd try the oil sending unit but as you know the autozone didn't have that so I got a manuel gage and mounted it at the block and and got 62 psi at 2000 Rpms and around 30 at idle. Oil they po lost i think came from loose (hand tight plug/ 3 turns from falling out) plug in the oil drain hose. Thank God if that was it!!!!

Can you all think of anything else.

Just did new fluids, plugs, fuses.

Mike Ingram
07-27-2012, 12:18 AM
Thanks again. !!!

thatsmrmastercraft
07-27-2012, 01:45 AM
Darn sending units.:(

Mike Ingram
07-27-2012, 03:07 PM
is that typical of a sending unit when its bad. Not sure how they work. Gonna get a new one and install it with the manual one at the unit

thatsmrmastercraft
07-27-2012, 04:27 PM
Oil pressure gauge sending units are notorious for reading low pressure when they get old.

Chrisoswald
07-27-2012, 05:51 PM
i hope its just the bad sending unit..if so id say you dodged a bullet. keep us posted

Mike Ingram
07-28-2012, 10:05 PM
Well
Today we took it out again and the pressure was great until it got hot and then it started dropping below 20 at slow idle and would hit 0. Soon as you idle up. Pressure is back up to 50-75. That's at the manual gauge I installed at the block. Any ideas. Need some direction.

j.mccreight@hotmail.com
07-29-2012, 12:39 AM
Well
Today we took it out again and the pressure was great until it got hot and then it started dropping below 20 at slow idle and would hit 0. Soon as you idle up. Pressure is back up to 50-75. That's at the manual gauge I installed at the block. Any ideas. Need some direction.

What viscosity oil did you change the oil with and what filter did you use? Use 15w40 and a wix, purolator, mobil1 or ford filter. If you have the orange can of death on it might have collapsed. If this is not the case I would try another gauge possibly a low pressure gauge if all this checks good and your still going to 0 psi at idle and engine is warm then you probably have crankshaft bearing that are worn causing the problem.

thatsmrmastercraft
07-29-2012, 12:07 PM
What viscosity oil did you change the oil with and what filter did you use? Use 15w40 and a wix, purolator, mobil1 or ford filter. If you have the orange can of death on it might have collapsed. If this is not the case I would try another gauge possibly a low pressure gauge if all this checks good and your still going to 0 psi at idle and engine is warm then you probably have crankshaft bearing that are worn causing the problem.

I agree but would go with Valvoline 20W/50 oil.

Mike Ingram
07-29-2012, 03:29 PM
Hey. I used castroil 20w50 and a mobil 1 filter. Could it be a oil pump issue. How would the crank shaft bearing affect pressure. Had not dealt with a bottom in before
Thanks.

j.mccreight@hotmail.com
07-29-2012, 05:12 PM
Hey. I used castroil 20w50 and a mobil 1 filter. Could it be a oil pump issue. How would the crank shaft bearing affect pressure. Had not dealt with a bottom in before
Thanks.

Diagnosing Oil Pressure Problems

http://www.enginebuildermag.com/Article/2418/diagnosing_oil_pressure_problems.aspx