Merc 240hp v6 wont start when in Water but will start when out

[Allstate]

Hello everyone. I am back again.

I have a weird problem.

My 240hp v6 m2 EFI motor runs fine untill I place it in water.
I recently replaced a powerhead along with some other things as well:
Fuel Pump, Starter, Fuel Hoses and Oil hoses.

Ok. This seems weird to me but here we go.

I noticed by pure luck and after a few trial starts and boat launching that I have come to the conclusion that the motor will not start when there is a "LOAD" on it. I believe it is a water problem because when you start the motor (No water hook up - I know bad thing) it turns and fires up right away. I also noticed that when yoiu connect the water hose to it "BEFORE" you start it with the water running - It wont start. Same as when I launch the boat in the water. Then after sitting in the driveway for about ten minutes with water shut off - it starts right back up.......

Does anyone have any ideas about this?

Manual really doesnt say much about it.

Also could there be such a load on it that the back pressure is not allowing this motor to start.


Thanks Allstate ........:boxing_smiley:

 

[robin savell lloyd]

On all the seadoos's I have seen you can not turn the water on before you start the engine or you will flood the cylinders with water and it will not start. I am not sure if mercury is this way. If it were mine I would find a site that have mercury engines in most all their boats. [ They need to have your type of mercury] Then do us and you a favor and post this site so we can steer others in the right direction. Please pm me this info so I can record it for the next person who has mercury question. Thanks Robin :cheers:

 

[darthspeed]

Mine does something similar, but if I connect the hose in the driveway it starts everytime. When mine occasionally occures it's after I am coming to a quick stop, like after a skier falls etc. and the water slams up against the back of the boat. My though was maybe the water is over filling the mufflers and possibly causing too much water pressure on the engine. If I turn the engine off and restart it, is the few times I have had a problem. I know that there is a water pressure sensor under the coils on the back of the motor. However, I have started the boat with the hose in the drive way and it seems to have no effect on if the boat will start or not. Also, when the boat is running when the sensor is unpluged the boat continues to run. This last Saturday, in 104 degree weather I just only turned off the engine a hand full of times and no problems starting. But.... I did notice that when I did start the engine it seems like there was more of a load on the engine when cranking. I think that the starter could really be the problem and is dragging when it gets hot after running awhile. I ran the engine for a good 4-6 hours, with no alarms and ran great all day. I think I will start researching problems on the starter. It seems our problems are close enough we can maybe figure this out together or if anyone else has any input. Thanks......

 

[Allstate]

Hey Darth, Thanks for your in put on this thing......But one thing bothers me is that I cant seem to find, at least on my motor, a water pressure switch located under my coil packs.

I am running a Year 2000 Seadoo Challenger 2000 240hp v6 m2 Motor.

Are we comparing apples to apples here? And if so, I need help to find this sensor.

I just spoke with a JETBOAT mechanic today and he said that the flush system works completely opposite in regards to the JETPUMP water intake.

What Do I know?......Im just a poor sole down 6g's and still no boat.

 

[darthspeed]

I post a picture......

When I get a few free minutes I will take a picture of the sensor. The sensor is at the top of the motor at the back. Then you can follow the grey tubbing down behind the coil pack bracket and to the block. I pulled the sensor loose on mine and was able to blow air into the block to make sure there was no obstructions. Also, I started the engine with the hose and water came out of the tubing. My engine should be very similar as it is a Mercury efi 249 hp.

 

[darthspeed]

Picture od sensor

Here is a picture of the sensor. Trace the tube to the block. The sensor is where my finger is pointing to.

 

[darthspeed]

Picture of sensor

Here is a picture of the sensor. Trace the tube to the block. The sensor is where my finger is pointing to.

I am posting some pictures of my audio system. 14 SPEAKERS and 1200+ watts!!!!!

 

[Allstate]

Pic of Sensor......?

Wow my motor doesnt seem to have that sensor or any hook up to the computer for that......MY engine is a year 2000.......Wondering if that was a new feature in 2001?.....

I will post a pic of my motor as well to compare apples to apples.....


Thanks.....Still no go in water

 

[seadoosnipe]

It's running!.....

Well, I see your engine is running!.......that's great. But I also see your still having more problems. The sensor he appears to be pointing at looks like the water sensor. It signals the ECM that the engine is flooded with water.

I guess we should have gone over all your sensors from the issues you were having but I did think that only the one sensor we went over was stopping you from running (due to previous issues from another member). It's obvious, that you may have more of them shorted or needing replacement. If you have someone un-qualified, power up the engine in wrong areas, testing things, then it's' easy to short out one of the sensors.

Do not turn on the water first, prior to engine start. Start the engine, then turn on the water. The suggestions to this in replies I've read in this thread are correct. After the engine is started, then turn on your water. The cooling on the water hose takes a different path than it does from your pump.

Outside the two sensors you already know about, the water sensor and the head temp sensor, the is a low oil switch, air temp sensor, throttle position sensor and head temperature switch.

There may be simple testing procedures in the manual for you to use a multi meter, testing ohms, that will help you determine which, if any of the remaining sensors are bad.

It's great to see you have someone in the forum with your engine. You are not comparing apples to oranges. You two basically have the same motor.

It sounds like you've come a long way and saved a lot of money, doing this yourself. Determination will eventually win out and this motor should be running soon....................congrats on your progress thus far.:cheers:

 

[jareaver]

Do not turn on the water first, prior to engine start. Start the engine, then turn on the water. The suggestions to this in replies I've read in this thread are correct. After the engine is started, then turn on your water. The cooling on the water hose takes a different path than it does from your pump.

Seadoo Snipe, I too have the 240 EFI on my 03' Islandia. I was looking at the operator's manual for the engine under flushing procedures. It states, " Flushing the cooling system is essential after each use in salt water, after the boat has been run aground, or when the overheat warning horn sounds. When using the flushing attachment make sure the water is turned all the way on and flowing through the engine before starting. When using the flushing attachment DO NOT run the engine above idle speed."

I know for the rotax engines you should never turn the water on before starting the engines (conversely, you never turn the motor off before turning the water off), but why the complete opposite for the Mercury unit?

 

[vilord]

The reason we don't turn the water on first for the rotax is that any pressure in the water jacket without the engine running will push past the gaskets and run into the cylinders, and possibly into the oil passages.

I would imagine the mercury (being a V6 instead of an inline 2) has a more robust cooling system. Additionally, unlike our rotax motors, the mercury flushing water can likely run back out by itself, whereas ours the engine needs to be running to push out the cooling water.

Aside... That says "DO NOT run the engine above idle speed"... am I not supposed to rev up my rotax when running on a hose? Or is that just for the Merc? I need to do so to clean/tune/test and would rather not do that in the lake.

 

[seadoosnipe]

jareaver....

Thank you for correcting me on this issue. I quoted the procedure from my experience, which is 99% of what I know, on the conditions and why, we start the motors first on the Rotax.

The reason, as I understand now that I've read this chapter, is due to the sensors on the V-6. The electronic control module uses these sensors to make adjustments according to the input from them. If the water sensor senses a lack of being flooded with water, either an incorrect fuel/air ratio or possibly, a no start situation may occur. What I wonder is, when the boat is first put in the water, there is no water in the engine (the M-2 is designed to gravity drain all cooling water), so how is starting and ECM adjustments made at the first few seconds of ignition?

There aren't a huge number of members using the M-2, so my knowledge is limited by input from other members and what I've learned in going over the manual. Which can be tricky since there are 3 different models covered, which have different characteristics when it comes to the electrical system. For example, the "turn key fuel enrichment" system on the 200 or 210 hp.....so, thanks again for all the input from any and all the M-2 owners.

We may have to look at putting together a section that covers just issues specific to the Mercury line of M-2 Optimax engines, to make it easier in your searching for answers. Keep an eye open for a section on them to open in the future..........

 

[robin savell lloyd]

Thank you for correcting me on this issue. I quoted the procedure from my experience, which is 99% of what I know, on the conditions and why, we start the motors first on the Rotax.

The reason, as I understand now that I've read this chapter, is due to the sensors on the V-6. The electronic control module uses these sensors to make adjustments according to the input from them. If the water sensor senses a lack of being flooded with water, either an incorrect fuel/air ratio or possibly, a no start situation may occur. What I wonder is, when the boat is first put in the water, there is no water in the engine (the M-2 is designed to gravity drain all cooling water), so how is starting and ECM adjustments made at the first few seconds of ignition?

There aren't a huge number of members using the M-2, so my knowledge is limited by input from other members and what I've learned in going over the manual. Which can be tricky since there are 3 different models covered, which have different characteristics when it comes to the electrical system. For example, the "turn key fuel enrichment" system on the 200 or 210 hp.....so, thanks again for all the input from any and all the M-2 owners.

We may have to look at putting together a section that covers just issues specific to the Mercury line of M-2 Optimax engines, to make it easier in your searching for answers. Keep an eye open for a section on them to open in the future..........

We may have to look at putting together a section that covers just issues specific to the Mercury line of M-2 Optimax engines, to make it easier in your searching for answers. Keep an eye open for a section on them to open in the future. Very good point Louis

 

[vilord]

Has there been any discussion of adding a small wiki for common problems and solutions? I know that Karl has a number of things already written up, and it is not hard to build the sections and search engine. MediaWIKI and others are easy to use and generally available as drop-ins from most service providers.

Then when issues are resolved the problem and solution could be added in an easily searched location without all the discussion associated in the forum...

 

[jareaver]

Thank you seadoosnipe for the explanation. I always found it odd that I had to turn the GTXs' engines on before flushing, and after for the Islandia. I, by no means, meant to hijack allstate's thread. I think having a separate section/wiki for the Mercury M2 is an excellent idea. I know there tends to be some confusion in threads b/w parts/info when it comes to Merc. vs. Rotax when information is sought (eg. wear ring/impeller repair and replacement).

Hopefully allstate can get the info/help he needs to get the boat up and running in the water soon!

 

[Allstate]

I seem not to have Water Pressure Sensor!........

Hey guys, thanks for all your support....

A section for the Merc m-2 Engine would be nice.....

But, I still go get the idea of my motor nor running in the water. I tried to find the Water Pressure Sensor that DARTH had showed a picture of in a previous post, but I dont seem to have that sensor. I looked all over where he is pointing to and I dont even have a spot for it( not even electrical leads for a hook up). I was wondering if there is a different MANUAL everyone else may be looking at. As per manual from this site. Look at wiring diagram for 240 efi Version. If someone can show me where on the schematic where that sensor is.

As far as hijacking my thread you bunch of terrorist. I love to hear what everyone has to say about other problems.......Again thanks alot.......:cheers:

As far as Seadoosnipe, check out my other post where we originally met I left you alot of praise. :angelsad::angelsad::angelsad:

I do know that I have a water sensor on the front of my motor under the ECM which I believe is the MAP sensor. I also have a TPS sensor as well (Throttle Postioning Sensor) would these have any effect on my issues....

I can follow flow charts and check Ohm readings, but when I dont have a direction in where to look I am lost.

thanks again

ALLSTATE

 

[vilord]

Okay to get back to your issue... You say it won't start at all in the water.

What does it do when you hit the start button? Does it crank and not turn over? Does it just sit there grinning at you and not make any sounds at all?
Does it click but not crank?

If you jump the starter relay (on my boat it is attached to the MPEM) will the engine turn?

I've got further questions, but they depend on what it is currently doing...
If it doesn't do anything when you hit the button, but cranks when you jump the relay, i'd venture a guess that there is a water pressure sensor somewhere that needs to be replaced, and would find out if you can unplug, short, or otherwise bypass it. EDIT: OR the MPEM is confused and not functioning properly

 

[Allstate]

Ok.......The motor will start when not in water....

When you put this in the water the motor just cranks but wont start......

lets back up a few steps...

I put the boat in the water when I installed a new fuel pump. I t ran fine. I lifted the the hatch to check for any oil leaks any funny sounds. I noticed that water was filling up in the back of the boat. (Due to the retarted Mechanic I had work on the boat didnt put block plug in). I returned to dock and went home and installed new block plug. To do this I had to remove the Exhaust chamber and coil pack plate. Due to location of plug. I then installed everything back the way it way and trippled checked everything. After that I placed boat in water and cant get it to run while in water now. Only when out of water.

 

[jareaver]

According to the M2 Service manual (1999 version) avaliable from this site, you should have the water pressure sensor. If I may point you to page 2D-3 (240hp wiring diagram, look at 'u' and 'v'), you can see both of those components are on the engine.

I just went out and took a picture of what you are looking for. It is from the stern of my boat, looking forward towards the bow. My computer here doesn't have photoshop, so I used paint to circle what it is you're looking for (sorry for the bad job).

 

[Allstate]

From this site look at mercury m2 engine shop manual............

Year 2000...........

I dont have this sensor on my boat.......Maybe they changed it.........

Your motor also looks a little different...

Let me take that same picture and show it to you

 

[vilord]

Is it possible the exhaust water jacket is clogged up? You could try pulling that plug back out and running it again

 

[Allstate]

Water exhaust Jacket may be clogged. But what I did notice was that "MY" water sensor is located below my COMPUTER as per manual 2000 m2 240hp in "OUR" manual forum........I just read this and want to go outside right now and check this but its 12:30am right now...lol.....

Also how can I check this sensor and test if this is good or not. Can I disconnect it to disconnect the short.

Thanks I will keep you posted.

:hurray: