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Changed impeller and found scale

J

jthomley

Member
"I have a 4.3l engine, with al

"I have a 4.3l engine, with alpha 1 gen II outdrive. I have reamoved the lower unit that holds the impeller and it looked fine. No fins were gone and very little wear, and I know it has not been changed for at least 4-6 years if at all (boat 2001).

BUT, when I lowered the lower unit, there was a fairly large piece of scale resting on the unit. A piece maybe as large as a 1/2 dollar.

Should I reinstall this lower unit, and look for more scale, or should I leave this off to be able to flush more scale out? OR should I sell the boat and get a new one?????? (just kidding, but who doesnt want a new boat?)

Thanks for any help!!!!!
Jasson.
"
 
Even though it looks good you

Even though it looks good you should at least replace the impeller and also replace the upper and lower housings (cheap insurance). Look into the upper OD for more scale hanging around and knock it loose.
 
"Thanks Guy!

I sure wasn&#3

"Thanks Guy!

I sure wasn't saying it didn't need replacing, just letting you know the condition. Keep in mind too, my boating knowledge comes from growing up that the ONLY thing we did to our boat was change the engine oil once a season!


I have a new thermostat too. Should I pull the old one and flush with water while the lower OD is off? And its a 160 degree, but I believe I have seen posts that it should be a 140? Can you please confirm.

thanks to all,
Jasson."
 
160 deg. F. is correct. Is th

160 deg. F. is correct. Is the engine cooled w/lake or sea water or does it use antifreeze and a heat exchanger?
 
"Jasson
Like yourself, Im con

"Jasson
Like yourself, Im concerned about the lump of scale you found siting on the lower box. It had to come from somewhere. Was it brown, like a lump of rusty cast Iron?"
 
"GUY, I could be mistaken here

"GUY, I could be mistaken here but I thought that non closed cooling was 143 degree and closed cooling ( heat eaxchanger) was 160 degree???

Also is your impeller housing stainless steel and the impeller 5 bladed long blades and soft?

if so you do NOT have to change the housing only the impeller. The housing is very durable and the impeller used in fresh water only can last a very long time as compaired to the older hard short bladed impeller in a plastic housing with a stainless inner sleve.

These newer impellers are very similar to the Johnson/Evinrude outboard impellers and last a long time."
 
"Mark-Yes! I was just a lump

"Mark-Yes! I was just a lump of rusty cast iron. I just went to find it, but could not. But yes, just as you described!

Kghost-I appreciate your opinion too! Yes, the housing appears very durable and the impeller is a fairly soft rubber with 5 blades.

Thanks for everyones help!
Jasson."
 
"If it was cast Iron, its time

"If it was cast Iron, its time to change your exhaust elbows. I once saw about two handfulls of rusty lumps sittin on top of the water pump, rubbing on the lower box input shaft. It was the rusted remains of the exhaust elbow rear extensions. Elbows were completely shot.
For peace of mind, remove the rubber exhaust tubes of the engine exhaust elbows, simple job, just a few hose clamps. If there are rusty lumps of cast iron floating around your exhaust system, They will corrode thru your alloy exhaust Y, which then lets water into the boat
(boat sinks)
. Look for more lumps at the two water drain holes at the bottom of the transom assembly. Only thing that doesnt make sense here is you boat seems to young for this to happen. If it isnt the elbows, that lump you found, still probably come down thru the exhaust from the engine. Mark."
 
I think there is a much bigger

I think there is a much bigger issue here than thermstat temps and impellors.....Mark.
 
"Mark-Thanks for the help too!

"Mark-Thanks for the help too! I mentioned the thermostat to be able to flush the water through, but maybe I need to check the elbows too. I have the service manual download, so I can reference that too. There is some slight surface rust where the exhaust meets the engine.

Sounds like I should just be considering my last option! Buy the new boat!
Naahhh! I like this boat, and you guys have helped me fix too much stuff on it already! Plus, who wants a boat payment in the winter.

Thanks, Jasson."
 
"Jasson

Just get them hose

"Jasson

Just get them hose clamps loose on the elbows, Youve gotta find where that rusty lump come from.
If youve got lumps of rusty cast iron sittin in the base of your exhast Y tube, next year you will be be pullin out the engine to change it...Mark"
 
"Kghost, Guy, and Mark- There

"Kghost, Guy, and Mark- There is some rust between the engine block and both exhaust manifolds (the manifold is connected to the block, right?). I pulled the 6 bolts and removed the port side manifold. I think it looks ok, some rust but did not find any scale.

There is some rust though, so how should I fix this? Should I just sand the rust and repaint with high temp paint? or what?

Now, how should I proceed to look for the scale?

Thanks,
Jasson."
 
Is the rust between the exhaus

Is the rust between the exhaust ports on the block? Or is it where the manifold meets the ports?
 
"Guy-Most of the rust is on th

"Guy-Most of the rust is on the manifold (the piece I removed), and very little on the block itself. I'm not at home right now so I'm not completely sure, but I dont remember any rust on the block.

Also, there are 6 bolts that hold this on, and removing them from bow to stern #3 and #6 had a lot of corrosion on them. The other bolts looked really good.

I have finally seen the flappers you have been talking about before ir other posts! The look good too on the port side of the boat.

The rest of the exhaust where the flappers are attached to, I need to inspect also? Is there another way to inspect other then looking down the flappers? Also, do i just clean the manifolds up myself (sand and paint) or would a muffler place do something extra I cant?

Thanks,Jasson."
 
"I would take the manifolds, r

"I would take the manifolds, risers and elbows to a radiator shop for cleaning and pressure testing. The shop will ultrasonically clean all the crap out of the parts. If you want to paint the parts when cleaned get some Rustoleum "Rust Converter" primer and spray all areas except mating surfaces where gaskets will be. Then put on one or two coats of Rustoleum engine enamel.

For the block remove the loose rust and paint the area the same as the parts. Cover the manifold mating surfaces before painting. When all is assembled touch up any bare metal on the block and other parts. I would also purchase new manifold bolts.

The "Y" pipe is checked visually. Use an awl to poke it where you see rust. If the awl goes thru then it needed to be replaced; pull the engine."
 
"<[img]"http://www.marineengin

"
294573.jpg
Photo of elbow with notes."">

Jasson, you still have not described condition of rear of elbow, You must find where that rusty piece came from.
Above is a photo of a good elbow, Ill try to get a photo of a rusty one and post that aswell.
The rust you have described on outside surface of exhaust and block, have nothing to do with the piece you found in the leg, sitting on water pump. Mark."
 
"Mark,

Thanks for the conti

"Mark,

Thanks for the continued help! I am not sure of what the pieces you have here. Is this the piece from the manifold and rubber gasket and then this piece? This is in the back part of the engine so I am not sure how this looks?

I did remove both manifolds and they both looked pretty good. Like you said above, about what they should for the age of the boat. I looked into where the rubber gasket was and could not find any scale at all! I know very strange.

I did find one of my on the starboard side of was not installed correctly and will be good that I will be replacing.

Plus after looking further today and into the lower unit, the piece of scale I found was way too big to come through the water pipe.

I am really not too worried now, since most of the signs are pretty good.

I do relize the rust on the surface of the manifolds has nothing to do with the scale, I just wasnted to ask what others would do about it.

Thanks,Jasson."
 
"Yeah, I guess you might not k

"Yeah, I guess you might not know that!


AND, for prior post I left out an important part. Sorry! In the third paragraph, I left out "Flappers" oops. Maybe now that makes more sense for that one. I found one of the flappers (one flapper on one side) was not down in the the exhaust tube at all.

An american quarter is about 1" in diameter, and a half dollar maybe 1 1/4" or so... For reference, it feels much bigger then a quarter.

Again, thanks for the help and concern!

Jasson."
 
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