1955 Evinrude 7.5

[Bellasdad]

I have a 1955 Evinrude 7518 7.5 hp. I had a problem with water coming out of the shifter shaft . I am not sure where it is coming from. I was told it could be the rubber bushing at the water pump/water tube connection or the base gasket at the power head or the head gasket. I bought all of these parts/gaskets . What would be the most logical cause ? or should I just replace all of them ?
Thanks in advance
Joe

 

[racerone]

I believe there is an o-ring on the shift shaft.----Pull power head to replace it.

 

[Bellasdad]

Thanks for the reply. Does that require a special o ring or can I use on from the hardware store ?

 

[Crosbyman]

marine o rings always seemed to be odd sized so it is best to get the real stuff

if by shifter shaft you mean the side handle then you may have a leak in the PH base gasket … very easy to replace
or inspect but has indicated you need to pull the head ..


just make 100% you get an identical gasket because patterns differ

in any event just pull the head and inspect everything just 7 bolts and a few parts/hose to disconnect see video

http://www.youtube.com/watch?v=SVOedhzPP7M

careful with the parts on top of the drive shaft (brittle carbon seal and loose parts)

 

[tomhath]

I believe you need to pull the power head to replace the water pump impeller, so while you have it off you may as well (if you haven't been there already).

 

[Bellasdad]

Thanks for all the replys. I am not going to change out the water pump because it seemed to be pretty strong judging by the spray it was shooting out of the shifter arm and exhaust. Does anybody have the part number for the shifter O ring ? I can't find a parts diagram anywhere to get a part number . Also when I put the power head back on , do you use any gasket sealer ?

Thanks
Joe

 

[racerone]

Well----You should change the impeller.----That motor does not have a warning horn .---It does not have a system to stop the motor should it start running too hot.-----So it would keep running till it destroys itself !!

 

[Crosbyman]

303191 is the shifter or ring on a 56 7.5hp …. probably the same as a 55 ?? ask IBOATS folks

you will need to pull the head since the shifter is connecter UNDER the PH in a cavity

while in there look around for the leak or bad gasket


no goo on the new gasket btw do change the impeller god or bad old fins can break off and plug things top side

 

[lindy46]

Is there water in the gearcase? That could indicate a bad shift rod o-ring, but not water "shooting out" the shift handle. Look at the powerhead base gasket.

 

[Bellasdad]

I decided to replace the water pump after all the comments . New kit impeller is a lot smaller than the old one.Part was upgraded.also got the new o ring for the shifter shaft. Old water pump doesn't look bad , blades are flexible and not broken.There is no water in the gear case .

 

[Crosbyman]

so.... did you fix the problem

 

[Bellasdad]

I haven't started to re assemble it yet, a little under the weather. I will try to get to it by the weekend. Will post update or ask more questions as I go. Thanks everyone for the help so far.

 

[lindy46]

If no water in the gearcase, I wouldn't go to the trouble to replace the shift rod o-ring.

 

[racerone]

Shift rod O-ring and / or the O-ring on the shift shaft that is below the powerhead.------Post # 1 indicates to me that O-ring below the powerhead is the leaker.

 

[Bellasdad]

Motor is finally back together. I replaced the water pump , the water pump kit that I got from the local Evinrude dealer BRP Evinrude/Johnson pn:0763758 has a much smaller impeller. The dealer assured me it is a direct replacement for the 7.5 hp motor.I also replaced the power head base gasket and all the parts directly underneath the power head and the head gasket along with the shifter O ring .I think I have all the bases covered now to stop any leaks up top.Did a compression test, both cylinders checked out equally at 70 psi.I will have to wait till spring to check it out in the water.

 

[thatone123]

Get a impeller...But...I have overheated the venerable OMC 15 2 stroke a number of times without destroying the engine! Always with synthetic oil being used.

 

[racerone]

123----Post # 15 says that a complete updated water pump kit was used.----This small impeller was first installed on the 79 model 6 HP------And yes that kit works fine on that old 7.5 model.

 

[Bellasdad]

Update on motor . I had it in the water today , the leak thru the shifter handle is gone. Bad news is motor won't idle but runs good at full throttle. I think the idle issue is that the lower spark plug is still getting water in the cylinder.With all the parts thrown at this I would think it was sealed up pretty good. New base gasket , new head gasket ( torqued to 6.5 ft pounds ) new seals between power head and lower unit, new water pump. What am I missing ?

 

[F_R]

"Still"??? You mean it has been getting water in the lower cylinder all this time? That isn't good. If it were salt water, you could just toss it out in the junk. Let's hope you get lucky.

Most often causes if water intrusion into a cylinder would be the head gasket and/or the exhaust cover baffle plate on the side of the powerhead. The plate often develops a pin-hole through it, which squirts water into the cylinder.

 

[racerone]

Guaranteed that the cylinder head was warped.-----Did you true it up on a piece of glass with emery paper ?