Is my impeller failing??

Before I start let me specify Merc alpha1 gen1. Engine is mcm185. a 3.8 liter V6 mercruiser similar to the 4.3.


So I dewinterized my boat today and started it up on the muffs. It took a while for water to come out of the exhaust but since the block was drained I figure no big deal.

After the engine had 5 minutes or so to warm up the water coming out of the exhaust was hot to the touch. Not scalding but just at the point where you could barely hold your hand under it. Temp gauge indicates no high temp.

The pee stream out of pee hole on the bottom of the lower unit was weak at idle, but fine if i throttled up to 1000 rpm.

I have no issues with having to change the impeller as it has been a few years and is due. I have a fishing trip planned for tomorrow and am trying to decide if I should make other plans or if I am just being paranoid.

Please don't beat me up too bad, I'm not trying to avoid changing the impeller. I'm just not sure if there is a problem or not based on what I see.

Re: Is my impeller failing??

I would think you are fine my water coming out my exhaust is hot to the touch I figured if the motor is 140 degress the water could be a tad hotter with exhaust mixed in with it. If it has been a couple years I would plan to install a new one when you get home just to be safe. Just keep an eye on the temp guage to make sure it is not getting hot. But I would go and have a good time.

Re: Is my impeller failing??

Please don't beat me up too bad, I'm not trying to avoid changing the impeller. I'm just not sure if there is a problem or not based on what I see.

Click to expand...

Ayuh,.... You can see it,.. I can't...
Take it with you tomorrow,...
At Worst, you can change it on the trailer at the launch....

Re: Is my impeller failing??

Thank you guys for the responses. I was really expecting to get beat up with would you risk your engine for a day of fishing responses. I'm pretty sure that the exhaust water has not been this hot before so I am going to the launch 5 minutes away. This way if there is a problem the drive of shame back home will be a short one. If it does overheat on the water I will end up needing a tow, which will hurt worse than the impeller replacement lol.

Re: Is my impeller failing??

If you use your boat quite a bit, I'd recommend changing your impellar and lower unit oil annually. It's cheap insurance....

Re: Is my impeller failing??

I do the lower unit oil every year when I winterize. I have slacked on the impeller and now I am the cliche about how deferring maintenance comes back to bite you.

Re: Is my impeller failing??

Rule of thumb I tell my customers is every other year for the impeller, yearly (at winterizing) for gear lube and pulling the outdrive for inspections and lubing coupler.

So, if your are concerned about your impeller and it has been used for 2 seasons, even if used for only a few hours each year. Replace it.
Then feel the water and you will have a base line to go by. Even the length of hose going to your muffs and the water pressure can effect the outgoing water temp.

Re: Is my impeller failing??

went out today, the impeller was fine. The fishing was slow and I forgot my anchor. The anchor thing ruined my trip and I'm lucky I didn't get stopped for a safety inspection.