400 Stringer - cooling system questions

mattsmall1972

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May 14, 2006
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OK, after 3 months of playing around, my buddy and I get to some serious work putting my boat back together so we can actually use it. I haven't heard the engine run since I bought the thing, and then only for a second so as to not destroy the impeller, which hopefully is good.

I hook up the earmuffs to what I think is the water intake - the slanted slots that are just behind the prop. I have the water blowing full blast, and we start playing with the engine. There's no prop on the motor at this time.

As we're playing with the engine, I'm noticing that a nasty black smoke is arising from the stern. I take note of the temp, and it's climbing steadily.

While still in the safe range, we are able to get the engine running smoothly. However, with the engine temp rising, we shut it off and let it rest.

After a while, I fill a large plastic storage container with water and am able to get water up past the water intake. I start the engine, it fires right up, nicely. The engine temp starts rising again after a minute, although not as fast. However, I am sure that water is circulating as I see a tiny leak from one of the water hoses on the engine. I'm thinking that this is not enough.

After shutting the engine off again, I see a black sooty, rubber-smelling drippage from the exhaust outlets from the holes just above the prop. I'm sure at this point that the impeller is gone.

Questions:
1) How can I conclusively tell if water is circulating properly while the boat is running with muffs?

2) Did I do the muffs properly?

3) Is the plastic bucket-o-water method safe?

4) Where does the water exhaust from? I never saw it either with the muffs or the bucket, although I imagine I might have missed it with the bucket?

5) Is there an easy way to determine the status of my impeller?

Thank you

BTW, I have searched the forums for answers, but the search is a bit goofy.
 

Reel Poor

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Re: 400 Stringer - cooling system questions

"1) How can I conclusively tell if water is circulating properly while the boat is running with muffs?"

The engine won't run hot

"2) Did I do the muffs properly?"

I'm not real sure on this one, I was thinking the there was a fitting that the water hose screwed into on those drives (not sure, it's been tooooo loooooong ago).

"3) Is the plastic bucket-o-water method safe?"

No, it's going to be insuficient.

"4) Where does the water exhaust from? I never saw it either with the muffs or the bucket, although I imagine I might have missed it with the bucket?"

Between the transom plate and the drive and also through the round hole in the back of the drive.

"5) Is there an easy way to determine the status of my impeller?"

Yep,,,Install a new one in the drive before you damage the engine and any other rubber parts that you didnt melt already while running the engine without sufficient water flow. Now you have an idea what the black goop was you saw, or it's fuel soot from running rich.
 

Boomyal

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Re: 400 Stringer - cooling system questions

Undoubtedly you cooked the impeller. There are good reasons why the say do not even run the motor for 5 seconds without water. In addition your shift cable runs right down the middle of the exhaust passaage in the outdrive. Without water in the passage you cook the casing on the very expensive shift cable.

Forget the container idea, forget the muffs, get yourself the water hose attachment that replaces one of the outdrive pivot caps. Then you can disconnect the line coming up from the intermediate housing to the thermostat housing and watch the water come out when you start the engine.

All this of course after you replace the water pump and inspect the shift cable.
 

Reel Poor

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Re: 400 Stringer - cooling system questions

I forgot about the shift cable. Good call Boom. ;)
 

whywhyzed

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Re: 400 Stringer - cooling system questions

I run my 800 stringer on muffs routinely...probably 30 times or more since I got it.... never had a problem.

The hose attachment is designed for the electric stringers that had the water intake above the prop, which made it impossible to put muffs on.
 

mattsmall1972

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Messages
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Re: 400 Stringer - cooling system questions

I'm not sure that the engine actually ran hot, just that I'm unsure if the engine was getting the water it needs. Does no water = hot?

I'm thinking that the impeller is certainly gone, but the soot may well have been caused by the engine running very rich as we had to correct a choke problem.

I'll dissect the stern and check the impeller.

Where do I get a hose attachment?
 

whywhyzed

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Re: 400 Stringer - cooling system questions

The hose attachment is designed for the electric stringers that had the water intake above the prop, not req'd for 400/800 as far as I'm concerned. But some guy used to make them up and sell them on eBay.
 

KaGee

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Re: 400 Stringer - cooling system questions

How can I conclusively tell if water is circulating properly while the boat is running with muffs?"

Look at the pee hole near the ball gear.

I have an 800 and the flush attachment is terrific!

Misc%20001.jpg
 

mattsmall1972

Petty Officer 1st Class
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Re: 400 Stringer - cooling system questions

Anyone know where I can get a hose hookup like that? I don't see them on ebay.
 

Boomyal

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Re: 400 Stringer - cooling system questions

KaGee said:
How can I conclusively tell if water is circulating properly while the boat is running with muffs?"

Look at the pee hole near the ball gear.

I have an 800 and the flush attachment is terrific!

Misc%20001.jpg

[colour=red]Geeeeeeeeeeeze, it's about time KaGee[/colour].:^
 

KaGee

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Re: 400 Stringer - cooling system questions

Matt,

Ebay is about the only place. They come in bunches.

You can try searching the net too... OMC part #173556

Boomer, I told you I installed it weeks ago!
 

Boomyal

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Re: 400 Stringer - cooling system questions

KaGee said:
Boomer, I told you I installed it weeks ago!

I musta been snoozin KaGee. Sure does beat the muffs don't it? IMHO those are reason enough not to switch over to those black anchors.;)
 

mattsmall1972

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Re: 400 Stringer - cooling system questions

Hi guys,
I pulled off the pivot caps to begin the disassembly of the top end of the stern drive to inspect the water pump. As I detached the stern drive, I noticed the gear shift and exhaust housing in there and started having some thoughts:

1) Inside both pivot caps, there was water where previously it was totally dry.

2) I believe the black smoke from the upper unit area was just exhaust - the engine had been running very rich, it had not been running for a long time and it never smelled like rubber burning.

3) The hoses on the inside of the boat were moist today when I pulled them off.

4) The small amount of black soot from the exhaust - probably just the richness.

5) I inspected the gear shift housing - it looks terrific, no problems.

I hate to pull the upper unit off just to inspect the water pump when all indications are that the water pump may be just fine, but that my water injection methods are a bit faulty. The whole thing even ran much better when it was in the bucket o'water.

My manual states that it's difficult to get the uppoer unit back together, that's why I'm pausing.

Opinions?

Regards,
Matt
 

Boomyal

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Re: 400 Stringer - cooling system questions

Gas and or oil do not smell like burning rubber. However at this point you can still put on your muffs, disconnect the supply line from the intermediate housing, at the thermostat housing and start the motor. You should get a solid stream of water out the end of the hose. If you don't or it is anemic, your pump is shot.

Another area you could be having problem is the thermostat tee itself. If it will not allow water to pass back thru the exhaust manifolds, you could have been cooking the rubber connection boots from your manifolds back to your intermediate housing. In that event you could still have a shift cable issue even if the pump is working. It's the return water, in the exhaust passage that keeps the shift cable from cooking. Also if the tree is blocked it will not let water circulate into the engine even if the thermostat is working.
 

mattsmall1972

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Re: 400 Stringer - cooling system questions

OK, I decided to err on the side of caution and disassemble the stern drive.

It was surprisingly easy to take everything off. The shift cable is in fine condition. I'm glad I got this thing apart because of all of the rusty manifold pieces that were in the exhaust. Don't worry, the manifold and riser have already been replaced.

Now I'm at the part where I need to actually remove the water pump. The four bolts on the bottom seem to be frozen solid. I'd doused them with WD40 and hopefully that will allow the bolts to break free. I have a breaker bar that I'm using, my problem is that I don't have anyone to hold this thing tight while I turn it - does anyone have any good suggestions as how to do this? Wish me luck.
 

Boomyal

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Re: 400 Stringer - cooling system questions

Don't use the breaker bar on them. If they snap you are in deep doo doo. Use a propane torch on the casing, around the bolt holes. Heat it evenly but do not burn the paint. Try tightening the bolts a litlle and loosening them a little. Use lots of PB blaster before and if you get them to move a little bit.
 

KaGee

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Re: 400 Stringer - cooling system questions

WD40 is not a penetrant. Use PB BLASTER.

Take your time.
 

Boomyal

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Re: 400 Stringer - cooling system questions

Wonder how our boy matt is fairing?
 

mattsmall1972

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Re: 400 Stringer - cooling system questions

I took the day off yesterday to cook for my wife. I'm going to buy some PB Blaster tonight and get back on the case.

I managed to find the stringer flush attachment on ebay by using the part number (thanks Keith!) and I have a complete water pump rebuild on the way.

This has been a great learning experience, I know everything will be fine.

Thanks.
 

mattsmall1972

Petty Officer 1st Class
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Re: 400 Stringer - cooling system questions

Hey guys,
I've got the 4 bolts off of the water pump. My manual states that the pump should pull up free at this point, but certainly will not. I followed the advice to insert a long bar into the steering hole and tap it, but that did not help free to water pump shaft.
This is my last step to disassemby - what am I doing wrong? I even tied laundry line to the shaft and tried a lever on it, but it's very stubborn. I feel like I'm missing something simple. Am I or is there a tool to use to get this thing free?

Thanks
 
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