Re: recirculate check valves 175 evinrude intruder
I have a 94 175 Johnson and this is how the factory manual says to check them. With the engine running at idle, remove the #1 cylinder recirculation hose from the fitting on the cylinder block and submerge the end of the hose in a cup of water and check for bubbles. Check all recirculation hoses before proceeding. Stop the engine. If bubbles appeared, check the block fitting with a syringe filled with alcohol. If the alcohol flows freely, the #1 cylinder recirc. system is okay. If it is restricted, you need to clean the cylinder block fitting.
If no bubbles appeared, remove the recirc hose and inspect it. If it is damaged, replace the hose and test again. If the hose is okay, you will need to remove the carburetors and intake manifold. Remove the #1 cylinders two check valves and check the manifold hose fitting with a syringe filled with alcohol. If alcohol flows freely, replace the two check valves. If the flow is restricted, clean the fitting and screen. This goes for the other cylinders as well of course. I hope this makes sense, the manual has some pictures to aid in the description.