# 04 200 hp Merc outboard - high temp alarm



## Nicevilleski (Apr 2, 2008)

This thing is driving me crazy. The I have an 04 200hp Mercury outboard saltwater, carburated. The alarm chirps when I am traveling slow about 1200 rpm's. The chirp comes from the alarm everytime I go over a wave. Sometimes when I am trying to bring it up on plane, I will get a steady alarm (high temp). The water is being discharged from the pump at all times, and the water pump was replaced in April, oh and so were the T-stats. I can go WOT and get no high temp alarm. I plan on changing out the water pump and looking for a loose wire behind the ignition and throttle area. 

Any other suggestions? (Well, I guess another good suggestion would be - park it and get ready for hunting season)

Thanks


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## sosmarine (Sep 28, 2007)

Could be a poppet valve opening to soon and bypassing to much water at low rpm.


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## Nicevilleski (Apr 2, 2008)

Will check that also. TY


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## The Maintenance Shoppe (Nov 5, 2007)

We have seen bad temp alarm sensors, blocked coolant passages, etc. Diagnosis $79 an hour. A laser temp gun would definitely help in diagnosing your engine.


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## Jighead (Feb 11, 2009)

Is this the motor with the blue wave on the cowing? runs off of 2 carbs then using the other 2 at higher RPMs? My suggestion, go trade it in ASAP!!! I'm not an expert, hell I don't even know how to change a water pump, but I had one and it was a piece of crap (2004 Merc saltwater 115). I even had a Mercury representative tell me that was the worst engine Mercury ever made:banghead. From what I've heard in trying to get mine fixed is there are numerous problems found throughout the model:reallycrying. I was told by my mechanic, and again I'm just going off what he said because I don't know, that it starts with electrical issues then somehow goes down from there. I believe it was my strator?? then another electrical part went then next thing I know my carbonators had to be rebuilt then it crack a cylinder.I bought it used andhave no idea the history.I gotvery lucky andwas able to tradeboat and motor inon anew one withoutloosing my shirt. 

I hope this is not the motor you have and if it is, I hope you get better service than I did. Maybe they are not all bad because I see them on the water all the time.


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## Nicevilleski (Apr 2, 2008)

Well, its been ok. I had it for 5 years now. Bought it new. I put a new pump and change out stats every year and water seperater and filter every 6 months. Let me tell ya... getting to the poppet valve is like doing brain surgery through your ass hole.... holy crap!

Still workin on it...:banghead


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## Nicevilleski (Apr 2, 2008)

Figured I would start a "required tools' list for this so far...........

5/16 wrench - short

5/16 wrench - long

5 /16 wrench - bent

1/2 bottle Jack Daniels

1 - mercury poppet kit

1 - 9mm with 7 rounds of SD ammo


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## Nicevilleski (Apr 2, 2008)

Poppet replaced. Hooked up a hose to the intake and ran the engine..... water comming from the weep hole in the poppet valve cover. Anyone know if this is normal?


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## DOUBLE "D" & LV (Oct 2, 2007)

Not normal. Should not have any water from the vent hole. The most likely issue after replacing one is that the screw holding the diaphram on is not tight enough or the diaphram is not sealing all the way. If you are getting the beeping noise when you hit a wave, then your engine tank is more than likely a little low on oil ( about an inch) allowing the float to drop just enough to sound the alarm. Make sure you do not have any loose hoses to the boat tank and that the caps are both tight. Check to see if the T-fitting at the hose to the engine tank (T is located on the starboard side) is leaking oil. If it is, replace it. Top off the engine tank if you found it low. For the overheat at midrange, poppet valve or water pump Sometimes the spring on the poppet valve gets stifffer than normal and it takes more pressure to open it. At midrange, there is not enough pressure when the spring gets stiff. You may need a new spring ( or cut off 3 to 4 rings). When you check the water pump, make sure that there are not any deep grooves in the center of the houseng or wear plate. If there are, replace them both.


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## DOUBLE "D" & LV (Oct 2, 2007)

> *Jighead (9/22/2009)*Is this the motor with the blue wave on the cowing? runs off of 2 carbs then using the other 2 at higher RPMs? My suggestion, go trade it in ASAP!!! I'm not an expert, hell I don't even know how to change a water pump, but I had one and it was a piece of crap (2004 Merc saltwater 115). I even had a Mercury representative tell me that was the worst engine Mercury ever made:banghead. From what I've heard in trying to get mine fixed is there are numerous problems found throughout the model:reallycrying. I was told by my mechanic, and again I'm just going off what he said because I don't know, that it starts with electrical issues then somehow goes down from there. I believe it was my strator?? then another electrical part went then next thing I know my carbonators had to be rebuilt then it crack a cylinder.I bought it used andhave no idea the history.I gotvery lucky andwas able to tradeboat and motor inon anew one withoutloosing my shirt.
> 
> I hope this is not the motor you have and if it is, I hope you get better service than I did. Maybe they are not all bad because I see them on the water all the time.


Sorry you had such a problem with yours, but those are good engines. Usually the reason someone says they are bad engines is because they can't tune them properly. They run great and use little fuel. The only real quirk about them is you have to get used to the 2 carb's kicking in about 2000 rpm if you are getting on plane slow. And his is not that one, his is a 6 cylinder. If you run across one that is not too much, let me know. I have someone that could use one.


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## Nicevilleski (Apr 2, 2008)

Well I did figure out the screw was not tight on top of the poppet. All is good. I have an exra T-fitting in case it ever spits oil out again. It did that a few month ago. I just clean it and the bearing frees itself and works well. Oil tank is full... I figure mabe the float is getting stuck. Will water test it on Thursday... gotta work tomorrow. Thank you for the replies. I guess I can scratch off the 9mm from the "tools needed" list.


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## Pinksnappertrapper (Dec 7, 2007)

Anything new?


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## Nicevilleski (Apr 2, 2008)

I will test it tomorrow.... if this does not do the trick, I will definatly be stumped.


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## Nicevilleski (Apr 2, 2008)

Water test done..... idled for about 25 minutes, pumped well...... got it up on plane, ran about 3 miles WOT, no problems. Trimmed it back down, was doing about 2000 rpm....kinda plowing...and after about 3-5 minutes...damn high temp alarm again. AAARRRRRRrr..... back to the drawing board.

:banghead


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## Pinksnappertrapper (Dec 7, 2007)

> *Nicevilleski (9/24/2009)*Water test done..... idled for about 25 minutes, pumped well...... got it up on plane, ran about 3 miles WOT, no problems. Trimmed it back down, was doing about 2000 rpm....kinda plowing...and after about 3-5 minutes...damn high temp alarm again. AAARRRRRRrr..... back to the drawing board.
> 
> :banghead


That is the exact same thing my 01 150 does. But i dont let it hit the alarm. I have a temp gauge and i shut it down around 180. Let me know what you find out and i will do the same. Im taking mine to kenny at emerald coast.


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## Nicevilleski (Apr 2, 2008)

Well I will try again Saturday. I am going to see if the alarm sounds with my T-stats taken out. If I get another alarm, I am going to tap on the oil regulator module ( I believe thats the name of it. Small black module above the spark plugs on top of the motor.) Then, I suppose I will remove the temp sensors, just to see if the alarm still sounds, if so...I will replace the alarm. 

Just a thought here.... I changed my lower oil today and it smelled burnt. No water in it... just a smell. I wonder if the lower unit was heating up the water going through the pump...causing an increase in temp to the engine? 

Oh well... still have archery season to look forward to.


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## Pinksnappertrapper (Dec 7, 2007)

You cant run it with the thermostats out, water will spit out where the black gasket goes. You can cut the to metal prongs and take the middle out and put them back in that way, but it didnt help mine. I have changed the water pump 4 times, thermostats, and pop it valve. I have a 55 gallon drum that i put saltaway in and ran the motor for 20 to 30 mins and it still didnt do anything. Good luck keep me posted.


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## DOUBLE "D" & LV (Oct 2, 2007)

Cut the poppet valve spring 3 to 4 rings.


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## Pinksnappertrapper (Dec 7, 2007)

I replaced everything in the popet except the two hard plates. Everything else including spring brandnew.


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## Nicevilleski (Apr 2, 2008)

Fixed! The lower unit oil had a burnt smell to it. I changed it with mercury lower unit oil. Ran it for 45 min at 2000 rpm..... no alarm:clap.

I guess the lower unit was heating up because of the oil being toast... causing pre heated water to enter the engine. 

DONE!:letsparty


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