1971 Johnson 50 Stupid Move !! and Stupid Question ??

[Jconnell43]

Spent the last month changing head gasket, thermostat, water pump etc as last trip last year it was overheating badly.
Parts were all trashed, little tough getting parts quickly these days.
Ran fine on muffs in garage.

Today I took it out on the lake 1st time, started Ok but wouldn't go over 15mph as opposed to 22 mph.
Overheat horn went off after 5 minutes and I shut it down immediately and trolling motored home.

This idiot forgot to open the vent screw on the gas tank (after 15 years of ownership ).

Questions:
Would this cause the engine to overheat? I thought the engine would just die.
When I had the lower unit off I noticed that the copper tube that fits into the water pump housing to send water up to the upper unit is not straight, it has a bend in it.
Is this normal, the end of the tube extends down about on a level with the end of the cast piece on the upper unit that the driveshaft fits in.

Knowledgeable posters will be remembered in my will.
Thanks,
Jim

 

[oldboat1]

Bend or a kink? Diff in mph would indicate something else is going on. Did you check compression?

 

[Jconnell43]

What I believe happened is the last time I lifted up the lower unit I engaged the driveshaft in it's cast tunnel but I didn't get the water tube in it's grommet.
When I tightened up the lower unit the water tube was not inside the water pump housing but was on the lip of it so tightening it up caused it to bend not kink.
After some thought I think that the overheating and the lack of gas caused my drop in MPH