Wierd Impeller performance

[Fl_Richard]

1995 Johnson 150 -- Just replaced the impeller, bought the kit. New plate gasgets etc.. Put her all back together and started it up. 3 Seconds later I had a good strong stream. let it run for a minute or two and throttled it up on the muffs to about 2200 rpm. Stream got stronger. Back to idle and it barely pisses. Shut dow immediately. Started it back up and nice strong stream -- Repeat -- Same thing barely pisses back at idle. Old impeller had constant stream. <br /><br />Any thoughts before I tear it all apart??<br /><br />Thanks,<br /><br />Richard

 

[jfm1]

Re: Wierd Impeller performance

not certain but I think idle on muffs would only produce a small stream

 

[Fl_Richard]

Re: Wierd Impeller performance

The strong stream when I first start it IS at idle.

 

[muskrat]

Re: Wierd Impeller performance

try running to at the ramp,you might not have enough water off you muffs.sometimes you might have enough water pressure but not a enough volume.

 

[DHPMARINE]

Re: Wierd Impeller performance

Those V6s hold quite alot of water.When you rev them up they pump out more water than your garden hose can supply,so the block has to fill up again.<br />Normal !<br />Are you sure the old impeller wasn't this way?Then maybe an oring is out of place in the pump housing.But I see lots of V6s doing as you explain,and they are fine.<br /><br />DHP

 

[Fl_Richard]

Re: Wierd Impeller performance

I broke out my old deep wheelbarrow and ran it for 15 minutes or so (along with some decarb stream never faltered. rinsed everything off, put the muffs back on and warmed it up to dry it off and same problem. This is surprising, there's always lots of water gusshing out the sides of the muffs. I'd swear it had plenty of suppply. <br /><br />I run the boat every weekend. (Ya gotta love Florida) I Rinse it religously, over watch the stream as the boats new to me and I've only put 100 hrs on it. <br /><br />I'm doing all the 100 hr/season stuff. So far on two motors I've found - 1-Cracked impeller, 2-black oil gearcases, 1-thermostat that magically unscrewed it's internal housing??? 1-dying VRO pump 12-identical lightly oily black spark plugs... and the list is growing... And this is a boat that runs awesome and has been well maintained.

 

[v12mac]

Re: Wierd Impeller performance

I had a simmlar problem that turned out to be air leaking in to the impeller housing due to an improperly seated pump asy. It would cool great untill I got up on plane and then it would loose all cooling flow. I'd have to shut down and restart to get it pumping again. <br />I guess I was just in a hurry to button everything up and didn't relise that the cup had rotated just a bit in the plastic pump housing.<br /><br />Mac

 

[Walker]

Re: Wierd Impeller performance

Muffs are not a good indication of the impellor performace. Not enough garden hose pressure can look like a bad impellor with a weak pee stream. A lot of garden hose water pressure can mak a bad impellor look good. A barrel test more accurately duplicates lake conditions.