657x air bleed back in oil lines

[Seadooguy12]

Hey guys, new to the forum. I have a 95 speedster with 657x motors in it. Rebuilt it for a customer but I noticed when bleeding the oil lines I would get them filled up with oil but then I would get some air bleed back and there would be a bubble right at the top by the intake manifold on both sides after I shut it off. Any idea why this is? Any help would be greatly appreciated.

 

[etemplet]

Check your bleed screwed to make sure it is tight. It might not have the copper gasket. Don't overtighten it... gentle but firm.

I have reused those little clamps as well on the hose attachments and have had to bend them a bit to make them fit properly. They do not grip 360 degrees and are only meant to stop the hose from coming off and not so much for sealing. If they are too tight (your hose size may be larger on the OD than OEM) they cam be the cause of your air leak. I feel better using small ty-wraps as they grip closer to 360 degrees. Don't make them tight.... just snug. Good Luck

 

[Seadooguy12]

Check your bleed screwed to make sure it is tight. It might not have the copper gasket. Don't overtighten it... gentle but firm.

I have reused those little clamps as well on the hose attachments and have had to bend them a bit to make them fit properly. They do not grip 360 degrees and are only meant to stop the hose from coming off and not so much for sealing. If they are too tight (your hose size may be larger on the OD than OEM) they cam be the cause of your air leak. I feel better using small ty-wraps as they grip closer to 360 degrees. Don't make them tight.... just snug. Good Luck

Thank you for the advice! the other side just had tie wraps but does the same thing , I never touched these lines when putting the top end in. Bleed screw was tight I’ll check to see if it has a copper washer but pretty sure it’s sealing because the air bubble doesn’t get larger and it is not leaking from it. The air bubble at the intake almost gets smaller the more I let it sit which is odd.

 

[etemplet]

You might just be getting capillary action in the tube from temperature and pressure changes. If the air bubble is not getting larger I wouldn't worry about it. Im concerned if I see a 1" section air bubble after I prime the lines. Good Luck !!!

 

[Seadooguy12]

You might just be getting capillary action in the tube from temperature and pressure changes. If the air bubble is not getting larger I wouldn't worry about it. Im concerned if I see a 1" section air bubble after I prime the lines. Good Luck !!!

Thanks! I would prime the lines to where they full. Then I would fire up the boat and then I would look and those little air bubbles right at the intake manifold. Then I would prime them until they were gone and it kept doing it. No air coming out of the pump side lines are full up until that point. Boat is definitely oiling just concerning to see the air in the line

 

[etemplet]

You can drop a little oil in the fuel tank if it makes you feel warm and fuzzy. Good Luck !

 

[burtshaver2021]

This is just a shot in the dark, never had it happen to me or anything but is there any chance that if the pressure release valve were bad on the oil tank causing a negative pressure in the oil tank I wonder if that could cause those small lines to draw back a little air? Anyone know if there are any check valves after the oil pump? Maybe in the banjo fittings? maybe this could be your problem, I don’t know, just throwing stuff out there