Evinrude Crossflow - Water Diverter Tubes

175HP 1990

My engine has been overheating. I am installing new water diverter tubes as they were swollen completely closed. My question is, is it normally required to have to trim the new tubes? They stick out from the cyliders about 1/4" which will cause them to be tight up against the head gasket when I put it all back together. Does this seem right? Any help is appreciated.

Thank you

Re: Evinrude Crossflow - Water Diverter Tubes

Make sure that they are seated down into the block.

(Water Deflectors)
(J. Reeves)

Water deflectors are actually lengths of 3/8" outside diameter rubber hose, installed between the top cylinder and any cylinder beneath it, and also between the bottom cylinder and the block. The purpose of the deflectors is to have the water follow a definite path around the cylinder walls. Unfortunately the deflectors between the cylinders will at times swell sideways due to either a previous bad overheating problem, or simply due to age and salt corrosion. This causes a water flow restriction which usually allows the water to cool sufficently at low rpms but not at the higher rpms.

This hose material can be purchased reasonably at any automotive parts type store if you care to make your own, or you can purchase individual deflectors at any Evinrude/Johnson dealership at a somewhat higher cost.

Removing and installing them can be a hassle at times, but not always. I use a sharply pointed scribe with about 1/4" of the tip bent at a right angle whereas I can reach in, jab the tip sideways into the rubber, then yank it out. It's necessary to clean the seating surfaces where the ruber contacts the block with a small rat tail file to eliminate salt deposits etc. When installing the new rubber deflector, coat the deflector and the metal surfaces with WD40 which will act as lubrication to allow it to go in as easily as possible.

Make sure that you insert something into that deflector area before cutting and installing the deflectors if you make your own so that you will be certain that they are the right length and also that they will be seated properly. Usually a very small amount will be left extending about the block sealing area..... simply cut the excess off with a single edge razor blade.

Re: Evinrude Crossflow - Water Diverter Tubes

Hi Joe,

Thanks for your response. The seat for the tubes will not allow them to go all of the way down to the hole where the water is coming from. With this design, how does the water find it's way into the tubes???? There is about a 1/4" or so from the water inlet to the tube. Am I doing something wrong or is this just the design? Also, with the tube pressed tight up against the head gasket, how does the water flow through?

One more question; the two tubes on the top line up with a hole in the block. As I mentioned above, there is a gap between the tube and the hole. The tube on the bottom bottoms out against the block completely. When I stick an awl through the hole in the bottom tube, it clearly hits the block. How does water get through that tube? It seems to be sealed off both from teh block and the head gasket.

thanks again

Re: Evinrude Crossflow - Water Diverter Tubes

You may have missed the purpose of the tubes. They do not pass any water through them. They are called diverters and that's what they do. They create a blockage in the powerhead to divert the cooling water in a specific circular motion around each cylinder for even cooling. If you have a factory service manual, the powerhead section will mention inspection of the cylinders, and that water flow diagram will show the circular movement of water through the powerhead.

Re: Evinrude Crossflow - Water Diverter Tubes

Thanks for your replies. After my last post last night, I had an "a-ha" moment and realized exacltly what emdsapmgr is talking about. I was looking through my manual and sure enough, there is a nice diagram in the back of the book that shows the circulation. It's amazing how things make more sense now. Thanks again!!

Re: Evinrude Crossflow - Water Diverter Tubes

As Emdsapmgr states above, you have mistaken the purpose of the deflectors. Notice that they are installed between the cylinders which effectively blocks/deflects the water from flowing to the other side of the cylinder. If they were not located in that manner, the water could flow across and between the cylinders to meet oncoming water from another path. This would result in the water flow encountering a stalemate where it would simply stop and boil away.

With the deflectors in place, the water enters the crankcase/block, flows up one side of the water passageway (keeping it simple) and down the other side.

Look upon the deflectors as a solid blocking component, not a water tube.

Re: Evinrude Crossflow - Water Diverter Tubes

dont know how old this post is but I just replaced my diverters. found that cleaning the area, basically craping it, blowing it out then apply grease to the tube. It still would not go all the way in. then I fugured out that you should apply pressure to the end to shove them in, at the same time take a small screw driver and push on the other end then all of the sudden there in. it takes a push and pull to get them in.