7.4 B3 Impeller

[ArizonaKevin]

I want to hit the mercruiser engineer in the head with a hammer for where they put the impeller on these. That is all

 

[ArizonaKevin]

 

[LargeOrangeFont]

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View attachment 1126988

The worst part is getting the stupid hoses off.

 

[guest hs]

They have to be low to draw water but I agree as well

 

[HST4ME]

Pussy, wait until you get into a twin engine v drive cruiser. You actually had room to work in.

 

[Mcob25rg]

It’s no better on the newer versions - 496HO, etc

 

[LuauLounge]

First time I did mine, it was over two hours to remove the pump, 15 minutes to put the new impeller in and 30 minutes to re install it. Took me two days to be able to move normally without expletives at every step or turn. The second time was about $500.

 

[Shlbyntro]

The trick is to take the whole pump off the engine.

wait until you try and do one on a new emissions controlled 8.2L

 

[Runs2rch]

Also unbolt the backseat and slide it forward or remove it.

 

[Racey]

Those ones are one of the easiest to change.

The 496 is a piece of shit.

The trick to doing those old v-belt ones is take the 4 bolts off that hold the pulley in place, remove the pully, now remove the pump and hoses, do the impeller on the bench, reinstall.

When you are done you usually don't even have to retension the belt, just pop the pulley back on.

The water pump has to be below the waterline to prime, so it pretty much has to go at the bottom of the motor.

 

[CobraDave]

On my 6.2 350 I think it took two days to do it. Now it will take me 30 min. Not bad as you just seperate the pump and remove the front half and change it on the bench. I haven’t done any other kind but the first time I removed all the hoses and that was an absolute pain in the ass

 

[farmo83]

True story

 

[Mcob25rg]

I got too old to do it on my head, so I take the rear seat out - takes longer to do that than the pump repair, but I can see everything - worth it at my age

 

[ArizonaKevin]

Yeah that's as far as we can move the seat without having to screw with perko switch wiring.

On my dad's Volvo penta small block it's much easier, impeller comes out the front instead of out the back

 

[FCT]

The trick is to take the whole pump off the engine.

wait until you try and do one on a new emissions controlled 8.2L

I literally just take my backseat out and then take it off it makes it simple. I’m not a contortionist so I don’t even try anymore

 

[Ryan00TJ]

You have mega room compared to my 496HO. I don't see any alcohol in your pics? Best tool to change impeller.

 

[Racey]

I got too old to do it on my head, so I take the rear seat out - takes longer to do that than the pump repair, but I can see everything - worth it at my age

It was worth it when I was in my early 20s

 

[boatdoc55]

Yeah that's as far as we can move the seat without having to screw with perko switch wiring.

On my dad's Volvo penta small block it's much easier, impeller comes out the front instead of out the back

That's because Volvo Penta engineers have 1000% more brains than the idiots at Mercury. Back in my day, working on the older stuff, who in the phuck installed the W/P IN the outdrive, of course Mercury, when all that was needed for a VP was flat tip screw driver and about 2 minutes.

 

[rivermobster]

I want to hit the mercruiser engineer in the head with a hammer for where they put the impeller on these. That is all

Good job on getting it done. How bad did the old one look?

 

[Racey]

That's because Volvo Penta engineers have 1000% more brains than the idiots at Mercury. Back in my day, working on the older stuff, who in the phuck installed the W/P IN the outdrive, of course Mercury, when all that was needed for a VP was flat tip screw driver and about 2 minutes.

That was a crossover from the outboards.

Alphas are a cheap entry level product. they used all the engineering already done on the outboard program, they shift in the lower unit as well for that reason.

 

[ArizonaKevin]

Good job on getting it done. How bad did the old one look?

It was toast, we noticed Temps climbing on the hose and changed it.

 

[ArizonaKevin]

 

[rivermobster]

View attachment 1127667

That looks about 5 years over due!!!

 

[ArizonaKevin]

That looks about 5 years over due!!!

1 year old

 

[Shlbyntro]

i would check your coolers and open up your thermostat housing and try and find those missing pieces before they cause a problem down the road

 

[MK1MOD0]

i would check your coolers and open up your thermostat housing and try and find those missing pieces before they cause a problem down the road

Truth right there.

 

[adam909]

You have mega room compared to my 496HO. I don't see any alcohol in your pics? Best tool to change impeller.

i have learned to never start drinking while changing the impeller on my HO.. As well as never change it on the water.. I have to be in a calm mood and know in my head that its going to fight me the entire time..

 

[rivermobster]

i would check your coolers and open up your thermostat housing and try and find those missing pieces before they cause a problem down the road

Absolutely. Plus, something had to cause that thing to so south in just one year.

There is a Much deeper problem somewhere that needs to be found before you run it again. @ArizonaKevin

 

[Shlbyntro]

Absolutely. Plus, something had to cause that thing to so south in just one year.

There is a Much deeper problem somewhere that needs to be found before you run it again. @ArizonaKevin

thats dry run damage, its not sucking

 

[ArizonaKevin]

thats dry run damage, its not sucking

Is it possible the rabbit ears we were running with the hose didn't get water up to it?

We ran about 5 hours yesterday and today watching the gauge like a hawk and didn't have any issues. End of the day, it's my FIL's boat so maintenance decisions get made by him

 

[LargeOrangeFont]

Is it possible the rabbit ears we were running with the hose didn't get water up to it?

We ran about 5 hours yesterday and today watching the gauge like a hawk and didn't have any issues. End of the day, it's my FIL's boat so maintenance decisions get made by him

Mine would not prime last time I changed the impeller and ran it the the rabbit ears. I took the boat to the ramp..30 seconds later it was fine.

 

[rivermobster]

thats dry run damage, its not sucking

Definitely got a tad hot.

 

[ArizonaKevin]

Definitely got a tad hot.

Oh yeah, as I was replacing it I brushed up against the motor mount and the exhaust, both were real hot

 

[Nanu/Nanu]

I only laugh as I have done this many times already in my two years of ownership and I think im a bit larger than you in a non muscular way haha! yeah mercruiser designed this horribly. to save yourself more heartache take your fuel pump off every season and change the 2 Oz of oil in there two if you havent. I use and have been told to just use the drive oil.

 

[Nanu/Nanu]

thats dry run damage, its not sucking

I think it definitely sucks!