2003 yamaha f40 impeller change

[CDory23]

I have always done the maintenance on my outboards and I know I should do the impeller every year but they always look brand new so I do it every 2 years. My port yamaha overheated because it was not cooling and it ruined a day on the water. Luckily I have twins so getting easy was fine even though it was a slow 8-9 mph

Long story short, it was time to change the impellers on them anway. I removed the lower unit and I don't think it has had any maintenance done to it in at least 5 years. The expensive marine mechanic shop that charged the original owner (who I bought boat from) also had just went through the carbs on there recent servicing right before I bought the boat and those had issues as well. After talking to other boaters I find this place has a bad reputation.

What I found was a decent amount of corrosion which I have cleaned up. The impeller was broken into many pieces and overheated the actual housing (plastic) so now I"m waiting for that part to get here to finish job. And the worst part the drive shaft was worn down in a small section (about 1.5") which I"m wondering if its due to the broken impeller forcing the shaft to bend out and grind against motor walls where it is inserted.

Pics of the driveshaft are in my album labeled "Shaft 1, 2"

My questions are :

1. When reassembling the lower unit do most use loctite or a silicone sealant to the bolts? I have used both but wondering the better choice, or maybe something different?

2. Is that wear in the shaft something to be concnerned about? Is it most likeley from the reason I stated above?

Thanks all for your help. Always appreciated.

 

[hardee]

My Yamaha mechanic (Twin 40's) says that the impeller needs to be replaced only every 300 hours. I have gone 3 seasons on one set, but now that I am using the boat more than a 100 per season it will be everyother year period.

I have no interest in coming home across Juan de Fuca on a single 40.

Harvey
SleepyC :moon

 

[BrentB]

a side question

How often do you change the thermostats?

 

[Sunbeam]

I have no interest in coming home across Juan de Fuca on a single 40.

Wait - did you just say something non-glowing about twins?! Let me just run outside and see if the earth has gone off its axis

 

[PaulNBriannaLynn]

I'd use some blue loctite on the impeller housing, and marine grease on all other fasteners and shift linkage.

The main reason to change the impellers more often than every 300 hours is to prevent corrosion. If it's been years since the lower unit was cracked off for inspection and new impellers, the salt can make it nearly impossible to get the bolts out and the corrosion can form sort of a weld between the aluminum and steel bolts, as well as the upper and lower units once the bolts are removed. This can be a real problem if the primary use of the outboard is in saltwater. Since a new impeller kit is only around $25, it makes a lot of sense to do it more often to prevent that from happening.

I'm not sure how serious that wear is on the shaft. If it were me, I would put it back together with the new housing and see if its got a strong "pee". Hopefully it does.

 

[PaulNBriannaLynn]

We caught our own fishing line in our port side motor one winter day fishing for blackmouth. Water was a little rough so it didn't seem safe to take the prop off and clean all that stuff out of there.

We motored back on one engine at 6-7 knots through the waves, and probably took us around 3 hours to get back to where the truck and trailer was. It was absolutely miserable going that slow!

 

[hardee]

I have no interest in coming home across Juan de Fuca on a single 40.

Wait - did you just say something non-glowing about twins?! Let me just run outside and see if the earth has gone off its axis

Sorry folks, (Some of you noticed there was a PNW earthquake just then) and the earth is not too tilted.

NOT, not glowing about twins, In fact, if it came to coming home on a single, across Juan de Fuca, I'd much rather it be on a single 40 than on a 6-10. On a single 40 I'd at least have half my horses still standing in the harness.

Harvey
SleepyC :moon

 

[Sunbeam]

I'd much rather it be on a single 40 than on a 6-10. On a single 40 I'd at least have half my horses still standing in the harness.

I hear you, although you'd have to change props to really "have" a single 40 properly pulling alone. Probably don't want to do that in the strait. I don't know what the HP equivalent is when it's propped as half of a set of twins though - I'd guess more than 6 but less than 40. It would be lugging some. Of course like a kicker, the idea is to get home or to safe harbor or anchorage, not to run at peak efficiency. I doubt the lugging would cause any issue for one trip home. I only mention it in case you didn't realize that the propping makes a difference and that you won't just instantly have "a single 40." I'm sure you could go faster than I could with my 5hp though