'81 15 hp rude water trouble

[Bruce San]

Just bought this motor from a guy who said he replaced the water pump impeller. I was able to run it briefly out of water and it started up and ran fine. I got it home and put the flush muffs on it and ran it. no water is coming out of the pee hole or exhaust. So I took the lower unit off. Sure enough, new impeller. everything looked like it was put together properly. I took the water cover off the head and it looks real clean inside. tried blowing compressed air up through the water tube from the bottom no air coming out anywhere it just pressurizes the tube and stops. Obviously something is plugged. Any ideas? do I need to remove the power head and start dissasembling it?

 

[Chinewalker]

Re: '81 15 hp rude water trouble

Hi Bruce,<br /> If you're getting nothing when using compressed air, then you've got a blockage somewhere. Could be an old waterpump impeller blade, sediment, corrosion, etc. Start by pulling the thermostat cover off, followed by the cylinder head, followed by the exhaust side cover. Be prepared to replace the gaskets for each. If you don't turn up the source of the blockage, then pull the powerhead off the lower unit. Just methodically work your way through the system and you'll nail it down... Not complicated or difficult - just time consuming.<br />- Scott

 

[rickdb1boat]

Re: '81 15 hp rude water trouble

Bruce San <br />First and foremost. NEVER run the engine without the lower unit in water(Not even for 30 Seconds). Fast way to destroy the water pump and the engine in short order. Have you removed the thermostat and checked to see if it has good water flow when running without it? Also, while you have the T-Stat out, stick the hose in the T-Stat hole and flush out from their. Diagram below:<br /><br />web page

 

[ICEMAN]

Re: '81 15 hp rude water trouble

Hi, Also a common problem with this motor is the upper water tube grommet closing off the water passage. You would have to remove the powerhead and exhaust megaphone to get to it. I've seen the grommet completely close off the tube.

 

[Bruce San]

Re: '81 15 hp rude water trouble

Chinewalker, Rick, Iceman, thank you all for your responses and advice! It'll give me an excuse to go work in the Air Conditioned shop tonight! It's getting HOT outside! 87 degrees today. Cutting the grass can wait!