Mercury 200 EFI Outboard - Cooling problems

[Ethe]

Hello.

I've got some problems with the cooling of my engine, and hopefully someone here is able to help me locate the issue.

From the top:
I was doing some service on my lower unit, changing the impeller and other parts, when I first noticed that the impeller was close to destroyed.

I ofcourse replaced the impeller, and I also had to remove some of the parts from the impeller as this was lying around in the lower unit (Looked like it had been running without water)

This did not actually help me anything
The problems escalated, and still I got no cooling in the engine.

The next ting I noticed was that there was some exhaust comming out of the water indication pipe going out of the engine, and realized that it must be a exhaust leakage into the water system.

So the next thing i had to do was remove the cylynder tops, replace the gaskets and also I had the cylynder tops to a mechanic, to check if they were flat, wich they were not.

I did this, and this did not either help.

The next thing i did was replacing all the parts to the impeller set, all the gaskets, and also the housing, and aswell the thermostats and blew compressed air and water with high pressure trough the water line, to be 100% sure that nothing was plugged up.

This picture will show you all i changed, from the parts #1 to #20.



This did not either help my problem, so the next thing I had to do.. Was to split the entire engine from the middle section of the engine, and checked for a exhaust leakage there.

The first thing I saw was not a pretty site, so i cleaned up, replaced all the gaskets and reinstalled everything.
This did not either help my problem.


Now I'm back controlling the Lower Unit.

I've tried to use a drill on the shaft in the lower unit, to see that the impeller blows water out, and it does.
I've tried to use a hose directly into the waterline from the middle section, up in the engine with the lower unit dismantled, and it works like a dream.

The only modification i got on the engine is a nosecone on the lower unit.


Can anyone help me to indentify the issue?

Thanks from Norway!

 

[Ethe]

Re: Mercury 200 EFI Outboard - Cooling problems

A little input:
The engine is a 1999 model, two stroke V6.

 

[Ethe]

Re: Mercury 200 EFI Outboard - Cooling problems

Does anyone got a suggestion to what might be wrong?

Thanks again

 

[Jlawsen]

Re: Mercury 200 EFI Outboard - Cooling problems

Is that a Bob's Machine lwp (low water pickup) nose cone and did you install it or did you send the Lower Unit to Bobs and have it installed?

 

[Ethe]

Re: Mercury 200 EFI Outboard - Cooling problems

Yes it is, I installed it myself, but it has been run with the nose cone for a cuple of seasons, and i dont think anything is wrong with it

 

[olsenk514]

Re: Mercury 200 EFI Outboard - Cooling problems

I had a similar problem on my Merc 225. Turned out to be a bad coupling where the water pump output meets the water tube. It was basically split in half, allowing the water to pump into the midsection, instead of flowing up to the powerhead.

Are you getting output from the tell-tale? If not, try running the motor with a thermostat housing removed, and see if you're getting water out of there. It will take a couple seconds to make it's way up from the lower unit. Also, are you getting an overheat alarm?

 

[Jlawsen]

Re: Mercury 200 EFI Outboard - Cooling problems

Pull the l/u off, put the nose cone on it and check water flow. I'm thinking the lwp's are plugged.

 

[Ethe]

Re: Mercury 200 EFI Outboard - Cooling problems

I had a similar problem on my Merc 225. Turned out to be a bad coupling where the water pump output meets the water tube. It was basically split in half, allowing the water to pump into the midsection, instead of flowing up to the powerhead.

I have a feeling that this is something of my issue aswell, but i removed the whole housing to the impeller, and fitted it on the watertube wich is going up in the engine, and it seemed to be OK, I can also see on the gaskets that the tube fits in when I install the lower unit.

Are you getting output from the tell-tale? If not, try running the motor with a thermostat housing removed, and see if you're getting water out of there. It will take a couple seconds to make it's way up from the lower unit. Also, are you getting an overheat alarm?

Yea I've been running without the thermostats for the entire time while im trying to fix the cooling. I got new thermostats ready for install but I dont want to install them before the problem is fixed.
No I am not getting an overheat alarm, I kill the engine in good time before that.

When I try to see if it works after a new installation, I usually take the boat on the water, so im sure that it gets water above the impeller, and run the engine in aprox 1 minute. then kill it when i dont see any water comming.

Pull the l/u off, put the nose cone on it and check water flow. I'm thinking the lwp's are plugged.

I maybe dont understand you correctly now, but you mean the lower water pickup right?

Anyway, i checked the Lower Unit by turning it with a drill.
I took it of, put it in a big bucket of water and used a drill at aprox 1100 RPM, and watched how much water that came out of the impeller, and it blowed water, I just havent checked how much pressure it can deliver.

 

[Jlawsen]

Re: Mercury 200 EFI Outboard - Cooling problems

First of all, the vanes on those impellers are short and tall. They are high volume, low pressure. At 1100 RPM you should have drained a big bucket in a quick minute. If you didn't you've got restriction in the nose cone. Just out of curiosity did you fill all the original pickup holes in the side of the lower unit or did you leave the top three open.

The other thing it could be is that you used the wrong coupler. Some of the kits have one the allows the tube to slide all the way down nearly down to the pump housing. The water tubes are cut to a precise length and if you have the wrong coupler it could be causing the tube to fall out of the grommet in the exhaust plate. You can just get a piece of thin wall 1/2" copper at Home Depot and cut it to the right length rather than ordering a new coupler if that happens to be the case.

 

[Dukedog]

Re: Mercury 200 EFI Outboard - Cooling problems

Tha "coupler" is there just to guide tha copper tube inta tha top of tha housing and inta tha grommet. It has nothing to do with anything else. On tha V6 anyway. Have you ran tha thing WITH tha new T-stats. Most will run hot without some type of restriction where they belong. No restriction tha water flows thru tha motor too fast and doesn't have time to do its job.............jmo

 

[Ethe]

Re: Mercury 200 EFI Outboard - Cooling problems

Just out of curiosity did you fill all the original pickup holes in the side of the lower unit or did you leave the top three open.

At the moment they are not filled up, but I know the issue this is gonna cause in high speeds, they will be plugged, and each time I tried to run the engine I assure myself that all the original pickup holes are under the water level.

The other thing it could be is that you used the wrong coupler. Some of the kits have one the allows the tube to slide all the way down nearly down to the pump housing. The water tubes are cut to a precise length and if you have the wrong coupler it could be causing the tube to fall out of the grommet in the exhaust plate. You can just get a piece of thin wall 1/2" copper at Home Depot and cut it to the right length rather than ordering a new coupler if that happens to be the case.

The design on this is like Dukedog said, the coupler is just to guide the copper tube from the middle section, to the lower unit, I've measured how far this go, and it goes nicely into the impeller housing.

Tha "coupler" is there just to guide tha copper tube inta tha top of tha housing and inta tha grommet. It has nothing to do with anything else. On tha V6 anyway. Have you ran tha thing WITH tha new T-stats. Most will run hot without some type of restriction where they belong. No restriction tha water flows thru tha motor too fast and doesn't have time to do its job.............jmo

Well the issue isnt that the engine gets hot, because I havent pushed it to that limit yet.
The issue is that I dont get any water indication out of the indication pipe, wich I do get when i just connect the engine to a water hose. I dont think that installing the thermostats will give me any other result than what I have experienced so far

 

[Jlawsen]

Re: Mercury 200 EFI Outboard - Cooling problems

Well the issue isnt that the engine gets hot, because I havent pushed it to that limit yet.
The issue is that I dont get any water indication out of the indication pipe, wich I do get when i just connect the engine to a water hose. I dont think that installing the thermostats will give me any other result than what I have experienced so far

I must have misunderstood, I thought you were burning up impellers. Put it on two hoses, one on the nose cone and the other on muffs covering the normal pickups. See what happens.

 

[Ethe]

Re: Mercury 200 EFI Outboard - Cooling problems

I must have misunderstood, I thought you were burning up impellers. Put it on two hoses, one on the nose cone and the other on muffs covering the normal pickups. See what happens.

I asked a local store about this and they said that there was no such thing to put over the nose cone (?)
Also there should not be any different to use a hose on the nose cone and a muff to cover the other pickups, than to lower the lower unit, covering both in the sea.. only that you get the pressure from the water hose

 

[Dukedog]

Re: Mercury 200 EFI Outboard - Cooling problems

Have you "cleared" all hoses that tie into tha discharge nipple? Had ta ask....When an impellar comes apart it will get pieces in a lot of places you just can't get to tha normal way. And there are a lot of those places in that motor. Block, heads, ex. divider, poppit, ex. adapter (both pieces) and etc. One way we've cleared debis. Pull gearcase and clamp a water hose straight to tha copper tube. Pull tha T-stats but put housing and hose's back on. Same with poppit. Turn tha hose on full pressure and let it run for a while. They can and will move around a lot if small enough. Yes there are a coupla different "muff's"made for lpw gearcase's. Did you say yours is a "Bob's"? I'll see if I can find a part number for it. If its tha one with tha exposed water tube on tha side just disconnect it at tha front and tie your hose into it there. If you still have tha inlets on tha side take a normal set of muffs, plud tha hose connection to use this to "block off" those inlets............D

 

[Jlawsen]

Re: Mercury 200 EFI Outboard - Cooling problems

I asked a local store about this and they said that there was no such thing to put over the nose cone (?)
Also there should not be any different to use a hose on the nose cone and a muff to cover the other pickups, than to lower the lower unit, covering both in the sea.. only that you get the pressure from the water hose

O.K. Clearly I'm missing something here. I don't think I can help you.

 

[Ethe]

Re: Mercury 200 EFI Outboard - Cooling problems

.When an impellar comes apart it will get pieces in a lot of places you just can't get to tha normal way. And there are a lot of those places in that motor. Block, heads, ex. divider, poppit, ex. adapter (both pieces) and etc. One way we've cleared debis. Pull gearcase and clamp a water hose straight to tha copper tube. Pull tha T-stats but put housing and hose's back on. Same with poppit

Yeah I've had water running trough to be sure that there is no parts from the old broken impeller inside the tubes, and I'ts not plugged up, because the engine runs fine when i take a water tube directly into the water tube in the middle section.

O.K. Clearly I'm missing something here. I don't think I can help you.

Alright let me try to explain the problem very easy, might be some missunderstanding due the language barrier.

The problem came right after the winter storage, when I tried to fire the engine up before the summer season.
I noticed that it didnt come any water out of the water indication pipe.
I did switch all the parts I wrote in the original parts, and checked for a exhaust leakage into the water system.
Now I have replaced all the parts wich got something to do with the cooling system on the engine, and all the gaskets wich separates the water from the exhaust. And I dont think that i get any water up in the powerhead either, because the engine gets really hot after aprox. 30 - 50 seconds of running.

One solution i came to think of yesterday:

The cover of the powerhead, is not original. It was switched by the last owner because this looks "nicer"
To be able to fit this cover, they mounted a metal plate between the middle section and the power head, so when i splitted the engine I noticed that there was two gaskets there.
One at the middle section to the metal plate, and one to the metal plate and the power head.

I ofcourse switched both when i changed this but what i think of now is that ofcourse this metal plate can be bent or something like that, its only about 3 - 5 mm thick.
If this is bent most likely there is a exhaust leakage there aswell, and changing the gaskets dosnt help me at all.

I also changed the "thermostat" that goes on the side of the engine yesterday, wich is beeing controlled by the "throttle"
That it opens more during high RPM.

Havent tried to run the engine yet but this is the finnaly last thing I can think of or else I have the sad feeling that I need to split the engine again.


Hope this helped you abit more to understand the issue.
No water circulation - in short words

Thanks from the cold North!

Eirik

 

[Dukedog]

Re: Mercury 200 EFI Outboard - Cooling problems

On top of tha motor directly behind tha flywheel there is a "pipe" fitting with a hose attached that goes down to tha "poppit" cover. Have you pulled tha hose from tha fitting on top when tha motor is running? Should get water there. That is tha very first entry point. Meaning there is nothing between tha water pump and that part of tha motor. If it pumps water to that area it shows that tha problem is somewhere in tha motor/exhaust adapter area.............

 

[Jlawsen]

Re: Mercury 200 EFI Outboard - Cooling problems

Eirik, O.K. we're communicating now. So you've got a motor that someone put an Alien cowling on and it now has the old style mounting plate, probably aftermarket but used primarily for Merc Racing motors. The Lower Unit has a Bob's Nose cone to make it act like a Sport Master so you can run a surfacing prop and still have good water flow to the engine.

You wrote

The problem came right after the winter storage, when I tried to fire the engine up before the summer season.
I noticed that it didnt come any water out of the water indication pipe.

Water of the indication pipe (we call it a tell tale) doesn't always mean no water flow but in your case I think it does.

You told me in another post that you put a drill motor on the drive shaft and the pump appeared to be working. I don't think it was working right. If it was you it would have shot a stream at least 1 meter high and your drill motor would have been very wet.

You also said that you put a hose on the water tube and cooling was good. That tells us that the problem is in the lower unit somewhere. You should be happy that you don't need to remove the powerhead again.

I would look to see if you might have sucked up mud into the lower unit on your last trip out before winter storage. Over the winter it dried and turned very very hard and is now at least partially blocking the water from getting to the waterpump.

You replaced what you called the thermostat on the side of the block. That is called the poppet valve and opens to get rid of the excess water that the pump produces. It usually starts to open around 1500 RPM. They need it because the water pumps produce too much water for the engine.

If you need me to try to explain it differently because of our language barrier tell me and I will try again.

 

[aussieflash]

Re: Mercury 200 EFI Outboard - Cooling problems

Put Tstats back in and test again.Without them you wont create any pressure in system to cool the upper block at idle and low speeds.
You have already proved no blockage by strong tell tale with hose direct to tube.