John Deere 404 Water Pump

[Cuckoos Nest]

Hello,

I have a 1976 Grand Banks located in Gig Harbor Wa. We are have having a really hard time finding someone who can rebuild a starboard water pump.

Issue: Currently our boat reads like its over heating but when you shoot a temp gun at it the engine is not hot. We changed the thermostat and that wasn’t it and my bill for peoples ‘guesses’ just keeps climbing.

If anyone has a suggestion where we can send this pump for a rebuild I sure would appreciate it.

Thank you,

The Cuckoos Nest
Gig Harbor, WA

 

[Comodave]

Welcome aboard. If it is showing hot and it really isn’t then I would guess it to be a gauge problem rather than the sea water pump. The pump must be working or else it would be actually running hot.

 

[Cuckoos Nest]

One would hope a bunch of mechanics would think of the simplest fix first. I’ll run your idea by the boss and see what he thinks. Thank you for replying!

 

[Nick F]

I have JD 6404s in my boat.

1 Are you talking about the raw water pump or the coolant (antifreeze) circulation pump?

2 as Commodave says above, if the temperature gun says the engine is not hot, then it probably is not hot and you have a gage problem. Its good to have twins, because you can compare temperatures from one to the other.

 

[Cuckoos Nest]

Coolant Circulation Pump. They checked all gauges and all are fine my husband said. And thats what the mechanic did, hit engines with a temp gun and both are the same.

The mechanics are now guessing its the pump, but no one seems to know who can rebuild it. And we will happily ship it anywhere.

Thank you for the reply!

 

[Comodave]

I still don’t see how a pump could be causing the problem if the IR gun says the engine isn’t overheating. If it isn’t overheating then how is the pump not working? What am I missing. Not a lot of confidence in the mechanics guessing…

 

[CharlieO.]

What problem are they trying to solve?
It's not overheating by shooting it for temps?
How did they verify the gauge was good?
Swap gauges and/or sending units from port to starboard?
Did they test the sending unit?
Check wiring and connections from sending unit to gauge?
^^ this is all based on that it is not actually running hot^^

 

[twistedtree]

Same question as others.... if the gauges say temps are fine, and a temp gun says temps are fine, then what's indicating there is a problem?

 

[Comodave]

Same question as others.... if the gauges say temps are fine, and a temp gun says temps are fine, then what's indicating there is a problem?

My impression is that the gauges say it is overheating but the IR gun says not. And the mechanic guesses the coolant circulation pump??? My guess would be to get a different mechanic. If the IR gun says it isn’t overheating then it probably isn’t. So that would indicate to me the gauges are wrong. He says they checked the gauges but how did they check them?

 

[twistedtree]

My impression is that the gauges say it is overheating but the IR gun says not. And the mechanic guesses the coolant circulation pump??? My guess would be to get a different mechanic. If the IR gun says it isn’t overheating then it probably isn’t. So that would indicate to me the gauges are wrong. He says they checked the gauges but how did they check them?

I took post #5 as saying the gauges read OK, but maybe that's not what was meant.

 

[Comodave]

Ok, not sure exactly what they meant. Maybe the OP will give us some more information.

 

[Bmarler]

Try this guy: Home
Small shop, does nice work. I rebuilt my pump myself, but this guy was very helpful supplying the oddball parts I needed.
No relationship with the shop.

 

[SteveK]

coolant pumps under one of the engine pulleys? If they are failing they leak, drops of coolant at least which shows as needing fluid to be added.

I always thought those were disposable items, you get a new one and install.

 

[GB42-424]

6404 opposite rotation coolant pump

I just rebuilt mine. Started weeping from the seal. The front and back plates and reverse rotation impeller are custom JD parts. Not available anymore. A replacement tractor pump will point the hose down instead of straight up. I walnut blasted the old parts before reassembly. Runs 10 degrees cooler now.

The bearing and seal are common parts. You'll need a shop bearing press, Bearing JD9257, seal AR 97882, seal press R518805, Gasket R50410, gasket R520254.

 

[Kurplunk]

I just rebuilt mine. Started weeping from the seal. The front and back plates and reverse rotation impeller are custom JD parts. Not available anymore. A replacement tractor pump will point the hose down instead of straight up. I walnut blasted the old parts before reassembly. Runs 10 degrees cooler now.

The bearing and seal are common parts. You'll need a shop bearing press, Bearing JD9257, seal AR 97882, seal press R518805, Gasket R50410, gasket R520254.

I am not able to open the attached file, can you try reposting it please.

 

[Nick F]

I am not able to open the attached file, can you try reposting it please.

It opened for me

 

[Kurplunk]

It opened for me

Yup, I got it to open also on the desktop - can't do it all on a smartphone.

 

[SteveK]

Yup, I got it to open also on the desktop - can't do it all on a smartphone.

try saving on phone and then open