8hp Honda impeller failure

B

bmacpiper

New member
Hello all,

Well, after a nice weekend on the water, a minor setback.

My 8hp Honda is a 2004, purchased this year with about 100 hours on it. The dealer stated in the ad that the impeller was changed before sale, and the motor has run well since I've had it. I used it as recently as yesterday for trolling, for something like an hour--it would have overheated if it wasn't getting water.

It has always been a bit hard to get a solid stream out of the telltale with earmuffs, but possible. Today, I was having a heckuva time flushing it with the muffs, and eventually submerged the lower unit in a bucket of water instead. Still no water, but some steam. Not a good sign.

I started to pull the lower unit, but thought I'd check inside the intake screens first. In there, I found bits of rubber that account for 3-4 fins from the impeller, so at least that mystery is solved. I also noticed that 2 of the 5 lower unit bolts are missing, and the others have blue loctite on them. So, either the mechanic forgot the loctite on the other two, or forgot the bolts.

In fairness, I have forgotten a time or two to turn on the earmuff water until after starting, i.e. start the motor, say "Oh S--t!", jump out of the boat, turn on the water.

So--did the impeller fail because it wasn't replaced, because it overheated due to lack of water, or something else I haven't thought of yet? The missing bolts really make me suspect of the quality of the labor, but also wanting to be fair about this.

Lastly, the Heloc manual calls for the shift linkage to be removed up top in order to remove the lower unit. The description makes it sound like a pin, with a straight shaft. My linkage is bent 90 degrees at the top, and I have a hard time imagining that part going through the case--can someone reassure me that it will indeed pass through once the grommet is out of the way?

Thanks and talk soon.
bmc
 
When flushing a Honda 8 using the ear muffs you usually need to block the third intake which is about 1 1/2" sq on the underside of the cavitation plate. Use a piece of duct tape. When it is not blocked there is a chance that it will be sucking enough air that the water can not get through the whole system.

Not to say that you don't have damage to the impeller. also you should check the thermostat to see if it is working. On top of the engine about 2/3 to the aft, 2 10MM bolts and carefully remove the top so as not to damage the gasket.
 
Anna Leigh":3lej6apn said:
When flushing a Honda 8 using the ear muffs you usually need to block the third intake which is about 1 1/2" sq on the underside of the cavitation plate. Use a piece of duct tape. When it is not blocked there is a chance that it will be sucking enough air that the water can not get through the whole system.

Not to say that you don't have damage to the impeller. also you should check the thermostat to see if it is working. On top of the engine about 2/3 to the aft, 2 10MM bolts and carefully remove the top so as not to damage the gasket.
Click to expand...

Thanks David. I've been able to get a reasonable stream in the past, but not what I'd call "solid", so that third intake is good to know about.

There is no question the impeller is trashed now--as mentioned, I have bits of it sitting on my desk. I'll have a look at the t-stat--I presume I'm just looking for any serious corrosion, etc. that might indicate it's stuck?

The motor has performed well on the water; I'm thinking this is just the impeller problem but will check all leads.

tx,
bmc
 
Hi again David,
Pulled the t-stat, and it moves freely. However, the lower passage was squeaky clean, where the upper had a bit of crud, i.e. bluish/greyish salt residue. Since I don't overheat during use, I'm guessing that this tells me that I need to flush longer, in order to warm up the motor and get the t-stat to open.

bmc
 
In 2006, I fried an impeller on a 2006 BF8 (new style) that had less then 20 hours on it. I was getting ready to go to the Broughtons and wanted to run the remainder of the gas out of the carburetor, using muffs. It ran for a minute or so, then started squealing like a big pig. Sportcraft advised me to never use muffs again.

This year when I changed the impeller as part of preventive maintenance, there was still some debris from the first impeller in the cooling system. It would occasionally block the pee hole, but would allow water through after I would stick a small nylon wire tie in the orifice.

Now, I either back the boat down to the water, or get out the flush bag to run the fuel out of the bowl.
 
Hmmm...there must be a linkage point up top that would allow the shift shaft to drop straight down or it must be able to disconnect from the lower unit side.
 
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