1971 Johnson 50 Water Pump??

[spike440]

Hi. Over the winter I plan to go through my old outboard. I have a manual, but it's not real detailed.<br /><br />The local boat shops around here won't work on it because, according to them, the solenoids are too fragile, and if they damage them, they are obsolete.<br /><br />Anybody have any tips for a total novice, forced to do his own repairs? I have loads of automotive experience, but have never touched a boat engine.<br /><br />I plan to replace the entire water pump assembly, go through the carbs, and replace the thermostat.<br /><br />Your help is greatly appreciated.<br />-Spiker

 

[usedboats4u]

Re: 1971 Johnson 50 Water Pump??

the hardest part about what you want to do is to get the lower unit down without breaking the wires that go to the lower unit, disconnect them at the power head, spray with wd-40 or such, i use fishing line to pull down with them for a fish tape on installation, then replace water pump. and reinstall, as for the solinoids they are avail from omc obsolete parts in ca.

 

[spike440]

Re: 1971 Johnson 50 Water Pump??

Thanks for the reply. One thing the manual doesn't specify is whether the oil needs drained before the water pump can be changed. Is the gearbox a closed system that can be removed intact?

 

[rolmops]

Re: 1971 Johnson 50 Water Pump??

No need to deal to with the oil.

 

[spike440]

Re: 1971 Johnson 50 Water Pump??

Thanks again. Another problem with my engine is the hot horn doesn't sound when the sender is grounded.If it's the horn, an I wire in an automotive horn to replace it? It has no guages of any kind so that horn is important.<br /><br />My gps says my top speed is 15.4mph. That sound about right for a big old heavy toon? It has a plastic mystery prop, and the slowest it will go is 2.2mph.<br />Thanks,<br />-Spike

 

[G DANE]

Re: 1971 Johnson 50 Water Pump??

Hi Spiker<br /><br />If you are having it on in exa a 17' runabout, i would say 15 is kind of slow. Try to calculate by this , earlier posted by JB:<br /><br />There is another formula for predicting top speed if ideally propped and trimmed.<br /><br />Prop HP=A<br />Boat gross wght.=B<br />Bottom factor=C: 180 for V bottom, 200 for nearly flat, 225 for Flat.<br /><br />Take the square root of A/B and multiply by C.<br /><br />Example: My Montauk has 70hp, weighs about 1900lb. with max load. 70/1900 =.037. Sq. rt of .037 =.19,<br />Nearly flat bottom factor, 200 X .19 = 38.4mph.<br /><br />GPS WOT reads 38.5mph <br /><br />--------------------<br />Red sky at night. . .

 

[spike440]

Re: 1971 Johnson 50 Water Pump??

Thanks! Wow this forum is great. I'm gonna just figure my speed is cool, too much math for me, lol. <br /><br />The only number I found so far for my water pump kit is 12232. I have some trouble navigating Iboats with webtv. Is this the number for an OMC kit? I prefer oem stuff.<br /><br />Thanks once again,<br />-Spiker