79 Evinrude Water Pressure Problems and More

[TrenchFisherman]

My friend has a 79 Evinrude 175hp outboard that is only producing 1lb. of pressure according to his gauge. He cleaned out the water tube and replaced the gauge and still nothing. The thermostats have been tested and everything seems fine. What else could cause this lack of water pressure. Also temp seems to be fine as well. <br /><br />Question number 2... I have a 86 evinrude 150 hp that i bought a new powerhead for. Inside the water jackets there is suppose to be some sort of device that blocks the water flow from going in certain directions for cooling. What is the technical name for those parts and can i just replaced them with some sort of gas hose? I don't know if that would hold up but is there any sort of other option than buying new ones? Any help would be great. Thanks a lot!

 

[thosch]

Re: 79 Evinrude Water Pressure Problems and More

1 lb of pressure is very low, even at idle. I would start with a new impeller for the water pump. Eve nis the guage is reading low, it is a good idea to regularly replace the impeller and/or water pump.<br /><br />For question #2, you are talking about the water deflectors. You can see them sitting in the water channels when you take the heads off. I would just buy new ones.

 

[TrenchFisherman]

Re: 79 Evinrude Water Pressure Problems and More

well i just asked and there is a new impeller in it. any new idea?

 

[wilde1j]

Re: 79 Evinrude Water Pressure Problems and More

If the pressure has been low since the impeller was replaced, I would suspect the grommet the water tube should enter may have been scrunched by the water tube end during installation. I usually make sure that grommet doesn't move by installing it with gasket cement, allowing it to dry thoroughly before installing the lower unit. Just for reference I have a 1985 Johnson 140 and it runs around 12 psi @ WOT, around 3 to 5 psi @ idle.<br />Jim

 

[thosch]

Re: 79 Evinrude Water Pressure Problems and More

Time to tear into the lower unit and take another look at the water pump. Also make sure the impeller blades are curved in the correct direction.<br /><br />I have a 1991 90hp Johnson. I also get 3-5 at idle and 14-15 at WOT.<br /><br />Out of curiousity, what is going on with the water deflectors?

 

[TrenchFisherman]

Re: 79 Evinrude Water Pressure Problems and More

when i bought a rebuilt powerhead i noticed that nothing was in there so someone told me to try and put rubber gas hose in there. at the time it sounded like a quick fix but now that i think about it maybe its not. Its at the shop now getting tuned up for its first run so i dunno if i should pull the heads off and put the right ones in or not. do you know where i can get them deflectors online somewhere? thanks

 

[TrenchFisherman]

Re: 79 Evinrude Water Pressure Problems and More

still around TH??? should i replace the tubes in the engine and do you know where i can get them online? thanks

 

[Dhadley]

Re: 79 Evinrude Water Pressure Problems and More

The water deflectors are indeed cut from the old double line fuel hose. dealers stock them and they are pretty cheap. Part number 322411.<br /><br />WildOne - I'll bet you are picking up your water pressure reading from the wrong place or your pump is severly worn. You should be reading from the adaptor plate on a looper, not T'd into the overboard line.<br /><br />Good luck!

 

[TrenchFisherman]

Re: 79 Evinrude Water Pressure Problems and More

dhadley thanks for the quick response. so i just have to go to a dealer and say i need cooling deflectors cut or are they pre cut? are they suppose to be flush with the top of the jugs?

 

[thosch]

Re: 79 Evinrude Water Pressure Problems and More

I think Dhadley is right on the mark. I slipped up in not thinking you had a looper engine. The crossflows are t'ed into the outboard line, but not the loopers.<br /><br />I would still buy the deflectors rather than cutting fuel line. Unless you have no access to a nearby dealer. Thank might have a bearing on my course of action.

 

[Dhadley]

Re: 79 Evinrude Water Pressure Problems and More

Just get 6 of those part numbers. You may find it easier to install them if you squirt them with some sort of oil. You may have to trim them flush with a razor. Not always but sometimes. <br /><br />Good luck!

 

[TrenchFisherman]

Re: 79 Evinrude Water Pressure Problems and More

ok dhadley and whoever can help...i called the local dealer and he has six in stock. he said they measured about 1 3/4 inches long. When i used the gas hose i believed the pieces i cut were around 3 inches long. Are they suppose to just push down to where they sit flush with the top on the cylinder? This engine has not been run yet since i put it together but its at the dealer getting timed and tuned up. I am kinda worried that when they start it that no water is gonna circulate through the heads because i jammed three inches of tubing in there. I hope this is all making sense.

 

[Dhadley]

Re: 79 Evinrude Water Pressure Problems and More

There isnt room for 3" of hose unless you put it in side to side and not front to back (straight in). Just get 6 of the correct thing (322411) and go from there. I know those will work correctly.<br /><br />Good luck!

 

[TrenchFisherman]

Re: 79 Evinrude Water Pressure Problems and More

ok...its been a long time so i am probably wrong. thanks for all the info...without you guys i would be in over my head with bills on this project

 

[wilde1j]

Re: 79 Evinrude Water Pressure Problems and More

Note to Dhadley: My pressure gauge installation was an OMC kit,installed when the motor was new, which consisted of the gauge, tubing, and a nylon tee, which was installed with model specific instuctions from OMC in one of the lines associated with the coolant valve operated by the throttle linkage. Reading has always been around 12 to 15 psi WOT and the water pump was new this spring. Possibly OMC's instructions were wrong?