Mercury 400 40HP 1971 - Should there be steam?

[nha]

Hi everyone - first post here so I hope I get some response.

I've just purchased a Mercury 400 40HP 1971 outboard and from what I know about outboards, water should be running through the engine and spitting out (sputtering out) at some location... Now I have located that location, near the cut off switch, but instead of water spitting out, it's a steady line of steam. Is this normal - should there be water spitting out or should it be steam?

Many thanks.

 

[AMD Rules]

Re: Mercury 400 40HP 1971 - Should there be steam?

Water cooling is mandatory. Steam implies it is not getting sufficent flow, or is simply too hot.

Either way, you need to determine why. Likely requires a new water pump impellor, and/or has a restriction in the cooling circuit.

Don't run it like that, or you will have a black anchor.

 

[nha]

Re: Mercury 400 40HP 1971 - Should there be steam?

Wow quick response or what! Great forum.
Thanks for the info AMD Rules, I've tried to trace the pipe, and it disappears into the depths of the engine itself, so I'm not sure if I will be able to clear it even if it is blocked. I'll take it to a local outboard shop, and see what they recommend - at least I know it's not a good idea to use it right now.

Cheers

 

[diaric]

Re: Mercury 400 40HP 1971 - Should there be steam?

if your mechanically inclined, you can do it yourself. search on here for changing impeller and waterpump repair. the difference could be a few hundred dollars compared to a shop.

 

[nha]

Re: Mercury 400 40HP 1971 - Should there be steam?

Hi guys,

Right I guess I am mechanically inclined (lol) so I've replaced the water pump impellor and cleaned the piping but the problem still persists. Any other suggestions? Could it be the water pump itself? Wish I had a manual so I could see what this looked like.

By the way - the impellor was in pretty crap condition!

 

[jebeebe]

Re: Mercury 400 40HP 1971 - Should there be steam?

Take your ser. no. and go to Mercury Parts Express and type it in and you will get a parts blowup and part no.s and prices.
I replaced the impeller and didn't fix it,...replaced the whole pump and it worked. Must have been a hole or a bad gasket in the lower houseing of the pump. Complete pump comes with new impeller, O-ring and driveshaft seal to keep the water out ou your lower unit..................Jerry

 

[diaric]

Re: Mercury 400 40HP 1971 - Should there be steam?

parts express doesn't work for old numbers, try this link. the seal the water tube fits in block can also be leaking. sometimes hooking a hose with a lowwater flow to water tube can sg=how you leaks and if its flowing properly
http://www.mercruiserparts.com/Show...desc=GEAR+HOUSING+ASSEMBLY,+COMPLETE+(PAGE+1)

 

[nha]

Re: Mercury 400 40HP 1971 - Should there be steam?

Hi fellas - thanks for the replies!

So the water pump isn't specifically a solid unit that just sits into the lower section? See I was expecting to see some sort of powered pump in there, perhaps something that ran off the drive shaft. So am I right in saying that the pump is actually only a small unit made up of the parts in the diagram in the link?

Guess I'll have to hope the shop has the other parts too

Cheers all... will post my findings once I replace the remainder of the pump.

 

[diaric]

Re: Mercury 400 40HP 1971 - Should there be steam?

this is the sort of kit you want. if you have no problems of water in your lower unit oil then leave the base alone and save the parts
http://www.iboats.com/mall/partfind...gd_poid=110926&gd_row=14&**********=006995827
http://www.iboats.com/mall/partfind...&gd_poid=111005&gd_row=6&**********=006995827

 

[outboardnut]

Re: Mercury 400 40HP 1971 - Should there be steam?

Hey can you see which wires are coming out of where on you're stator? I have one I'm trying to repair.

You want to replace you're water pump impeller. The sierra part number is 18-3007.

The most cricitcal thing when you do the job is make DOUBLE SURE you line up the **** tube with the water pump hosing on the lower unit.

I'm getting ready to do the one on my 71' merc 400. If you need directions just let me know.

If you could tell me what wires coming from you're stator are what color I would really appreciate it. Somebody rewired mine before I got ahold of it...and the stator was disconnected. Only way I can fix this stator is know what color of wires come from where!
http://forums.iboats.com/showthread.php?t=216673

 

[nha]

Re: Mercury 400 40HP 1971 - Should there be steam?

Hi guys after replacing the impeller with no joy, we went ahead and replaced the whole water pump and the problem has been resolved - obviously a leaking gasket or casing! And yes we did have a job making sure the pee hole pipe was slipping into the lower unit - but that is in properly. Thanks for all the help!! Great support.