cooling on a 70hp merc

[rperre]

Hi, I just rebuild this engine and it idles fine, but I don't see any water coming out of the pisser in the back, after a while just some steam, what can this be!<br /><br />Although when I had it at my home and hooked up the flush flapper things it did squirt water out of the pisser!!!!!<br /><br />I did rebuild the waterpump too!<br /><br />What can I check?<br /><br />Richard

 

[rperre]

Re: cooling on a 70hp merc

also can I take out the thermostat, or do I have to leave it in?<br /><br />Richard

 

[CU2NITE]

Re: cooling on a 70hp merc

Leave the stats in, also I would suspect the water pump due to the fact that you are getting water out of the pisser when useing the muffs but not on the water. When the muffs are used it pushes water up into the motor. I know you said you rebuilt it but I would double check to make sure it was done correct. If you have been starting the motor dry you could have burned the impeller. Good luck.<br />CU<br /><br />-------------------<br />RUNNING THE MOTOR WHILE LISTENING TO THE HORN WILL MAKE YOU MORN!!

 

[rperre]

Re: cooling on a 70hp merc

Thanks, yeah I was going to take the bottom end off next, and I'll put the stats back in!<br /><br />Richard

 

[Keith Buchanan]

Re: cooling on a 70hp merc

When you have the bottom end off attach a hose to the water takeup tube and run your engine for a while, monitor the temp of the pee stream and look for any signs of steam, if all is well take a closer look at your pump. Report back here..

 

[rperre]

Re: cooling on a 70hp merc

hey took the bottom end off and looked at the impeller, it was totally shot, bought a new one, I guess I ran it dry for a little!<br /><br />I'll put it in and report back,<br /><br />Richard

 

[CU2NITE]

Re: cooling on a 70hp merc

Glad you found the problem. Starting a motor even for a few seconds out of water can cause the impeller to fry. I learned the hard way also!<br />CU<br /><br />---------------------<br />RUNNING THE MOTOR WHILE LISTENING TO THE HORN WILL MAKE YOU MORN!!

 

[Merc805]

Re: cooling on a 70hp merc

Funny about that theory.. There is a guy who I have witnessed on 2 occasions over 3 weeks who takes his Black Max Merc to the local ramp and dry starts it on the trailer with NO water anywhere near it. He also revs it like a big V8 car until fire backfires out the prop <br />I said to my wife.. "That would have destroyed his impellor" but nope.. he lauches and takes off with a stream of water and operates the boat for 20 minutes with no issues. Couple of weeks later he is back with the same procedure.. Maybe impellers only self destruct on peoples motors who care... I was going to go and tell him but was afraid he may have said he's been doing it for centuries...

 

[CU2NITE]

Re: cooling on a 70hp merc

It's a very short matter of time before you don't see him at the lake any more. I have a 150 black max and have burned the impeller twice. First time I ran it dry when I just bought it(just to hear it run), and the second time I didn't have the muffs over the water intake holes(I pushed it to far forward) I'm very careful now to never start it dry. Just makes sense that the friction of the impeller spinning with out lubricant (water) will get it hot and be destroyed. That guy you see will learn the hard way, like I did.<br />CU<br /><br />--------------------<br />RUNNING THE MOTOR WHILE LISTENING TO THE HORN WILL MAKE YOU MORN!!

 

[Keith Buchanan]

Re: cooling on a 70hp merc

Yep, I did the same with my first O/B, just to hear it run, £20 impeller, £36 exhaust manifold and water cover gasket and witnesses on this forum will tell you I tried for three weeks to free the drive shaft splines when I attempted to drop the lower unit. Steep learning curve certainly but Rperre your'e definately in the right place for terrific advice and support, stick in there ...<br /><br />Regards Keithy B... Hey I didn't know you could use more than one..Ha! Ha!..<br /><br />Keep it simple..