Dt65 oil injection

3

3ric

Petty Officer 3rd Class
Joined
Nov 11, 2020
Messages
94
I have a 1985 Suzuki dt65. The oil injection does not work properly. The oil only pumps to the impulse ports/check valves on the crank case, but not past. Today, I removed the hoses from where the connect to the intake and filled them with oil. The top cylinder hose held oil, but the #2 just drained into the crank case through the impulse port/check valve. I can’t remember what the bottom cylinder hose did. I also re-bled the pump (only one tiny bubble seemed to come out).
Question #1. Are the check valves/impulse ports replaceable? They come right out of my 1987 parts motor with a firm wiggle and pull. But the 1985 valves are round (hard to grip) and seem to be in tight enough I can’t remove them without destroying them.
Question #2 is there a name for the check valves/impulse ports on the crank case? Where can I get replacements?
Question #3. Can I use the valves from my 1987 dt65 parts motor. Will they fit?
Question #4 if the one crank case impulse valve is malfunctioning that bad, would it absorb all the pump pressure and reduce the pressure on the other two lines?
 
Sea Rider

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
Oil check valves are replaceable, the issue is trying to remove them when have already been molded to the internal rubber hose, can replace the whole hose and install a new check valve at their specific end, check the valve sits at its correct working position when installing it. Other alternative, cut current hose, remove current check valve and install same on a new rubber hose. If the check valves are not working properly replace them or risk frying any internal bearing and associated parts.

Happy Boating​
 
Last edited:
3

3ric

Petty Officer 3rd Class
Joined
Nov 11, 2020
Messages
94
Thank you for the reply. The inline check valves all appear to be operating fine. It is the 3 way check valve that mounts into the crankcase, that I was told is where the oil gets a bump of pressure to continue to push the oil on to the intake manifold. The #2 hose leaks down into the crankcase at this valve and I don’t think it is supposed to
 
3

3ric

Petty Officer 3rd Class
Joined
Nov 11, 2020
Messages
94
Sea Rider said:
I'm not familiar with said motor but know well the oil check valves. Here's the oil pump schematic where 3 check valves are mentioned, part number 13.


Probably the oil pump line has air, need to open the air valve and purge it, check the Owner's Manual for that procedure.

Happy Boating​
Click to expand...
I think I figured it out. When I got the motor, the system was a bit grimy. So I blasted some air through the valve, and when I did, I think I blew out the part of the valve that keeps the oil from flowing into the crankcase. I figured out how to pull the ports out and found they were not working. I have some new (used) ones on the way so hopefully they will do the trick
 
3

3ric

Petty Officer 3rd Class
Joined
Nov 11, 2020
Messages
94
3ric said:
I think I figured it out. When I got the motor, the system was a bit grimy. So I blasted some air through the valve, and when I did, I think I blew out the part of the valve that keeps the oil from flowing into the crankcase. I figured out how to pull the ports out and found they were not working. I have some new (used) ones on the way so hopefully they will do the trick
Click to expand...
Ok, so I have had a few opportunities to really test out the system. Unfortunately I am left with unsure results. I have bled the system correctly, or so I think. And the motor appears to be consuming oil properly. However, after use, overnight, the oil will drain out of the oil lines between the intake and the crankcase, presumably into the crankcase, as it never drains past the check valve at the crank case. It does this on all three cylinders.
Is this normal? I am afraid that A. It leaves a bunch of oil in the crankcase resulting in a temporary over abundance of oil and B. It will result in the engine being oil starved until the pump fills the 3 or so inches of oil line again.

Are my fears valid or is the oil supposed to go into the crankcase?
 
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