Mercury 200 overheating!!!

[Phantom200]

Hi people I new to the site and after alittle help as I'm at a loss! I have a mercury 2.4 200hp and keeps overheating when anything past 4000rpm I have changed water pump,thermostats,head gaskets,poppet valve spring even changed the gearbox for a deep water pick up! My engine is std as dad as I no but I am running the offshore mid section with the new style cowling and help would be great as I'm lost as to what to do next. If you run the engine on tick over its fine as soon as you bring the revs up you can feel the temperature of the water coming of the tail getting hot quick!

[transomstand]

Need your water pressure readings and actual temps. Without them, it's just guessing and throwing parts at it.

[tlwjkw]

I am running the offshore mid section with the new style cowling
One piece adapter?

[Forkin' Crazy]

One piece adapter?

That would be with a big water tube?

[ssmith007]

Blockage or leak?

[tlwjkw]

That would be with a big water tube?
Depends on tha year............What I've seen stock stuff (T-stats, poppet, no diverters) don't seem ta work well with tha one piece.............

[Phantom200]

Depends on tha year............What I've seen stock stuff (T-stats, poppet, no diverters) don't seem ta work well with tha one piece.............
My engine is a 86-88 so quite old has good compression all over 130psi when flat out I have the over 30spi water pressure so no the pumps working I'm thinking of making a plate same as the do on the xr2s on the poppet valve and dump the water outside the tray as I'm thinking I may have a problem with the way it dumps it through the offshore midsection?

[tlwjkw]

Depends on tha year.............
This is referin' ta tha size tube tha one piece adapter plate uses........If your motor is still all chrome and ya gotta one piece adapter ya might oughta set tha whole coolin' system up just like a stock 260 nic motor n go from there..............

[Phantom200]

This is referin' ta tha size tube tha one piece adapter plate uses........If your motor is still all chrome and ya gotta one piece adapter ya might oughta set tha whole coolin' system up just like a stock 260 nic motor n go from there..............
Yes mines a 86-88 motor chrome boars std with the 20" offshore mid section and cle two gearbox

[Phantom200]

Hi guys any help would be great do you think I have a flow problem between the mid section and power head?

[Steve Pope]

Remove the exhaust chest covers and check for blockage in water feed holes leading into block.

[tlwjkw]

set tha whole coolin' system up just like a stock 260 nic motor n go from there..............
This is what ya need ta do with a one piece adapter. If ya mix n match coolin' systems ya gonna be chasin' your tale tryin' ta run down problems.............

[Phantom200]

Ok so we removed the power head replaced the gaskets and checked everything removed the poppet valve completely as its just dumping the water in the the sandwich plate and can't get out only through two tiny holes now there's a plate on the side of the poppet valve and domes the water out side the tray and a second on from the top of the head on the other side went out had good water flow but once again the alarm goes off with 10psi and both pipes pumping water??any help as what to do next??

[Phantom200]

The head were reading about 60-70 when the alarm was going off measured with a infa red

[phillnjack]

who said that 60 to 70 degree's is overheating ?
that is normal running temp if you have thermostats fitted properly and working good.
soundd like you have dodgy alarm sensor, as 70 is not overheating surely.
the average car engine runs at 88deg C, my merc 60 ran at around 70 degC as well.
my 3 cylinder evinrude runs between 60 and 70 deg C all the time as well.
i am not 100% on the size of your engine but i wouldnt say its anywhere near over heating, just a dodgy sensor that needs replacing.
what does the workshop manual say for temp on that engine ?

[Phantom200]

That's what I was thinking but the alarm is going off yet the engine didnt seem hot I have even replaced the overheat switch at the engine as I thought this may of been the problem all along but with a new alarm it's still doing it?

[CharlieB53]

By 'new alarm' you mean you replaced the temp sensor?

Have you checked engine timing? Too much or too little ignition timing will cause a motor to heat.

A dragging timer lever not allowing the timing to reach the WOT timing limit making the WOT timing retarded will heat at and near WOT yet seem fine at lower throttle.

[Phantom200]

Hi all just tested my overheat alarm and its set to go off at around 160f in the mercury book it shows mine should be set at 240f think this is the problem?

[transomstand]

Sounds like you're using the early switch, they went off at about 180° F, the newer one goes off about 220° F.

[Phantom200]

Think your rite that's my problem what should my engine run at when flat out???

[transomstand]

140 to 160 is about right, if your maxed at 70C, that converts to 158F, and should be fine, provided your temp measurements are accurate.

[transomstand]

http://i221.photobucket.com/albums/dd58/transomstand/A%20uploads%202013/tempsender-1.jpg (http://s221.photobucket.com/user/transomstand/media/A%20uploads%202013/tempsender-1.jpg.html)

[Phantom200]

Thanks mate for the info mine needs the 240f overheat sensors just got back flat ou at 6000rpm the heads read 130-140f alarm going off of course but 15psi of water and only warm!

[Phantom200]

Can any tell me the part number for the 240f overheat sensor??

[transomstand]

P/n-97465

[mach1magnum]

check temp sensor with a known good one

[Phantom200]

That's the thing I need to get one but don't no the part number??

[Phantom200]

Hi guys have the rite temp sensor now I'm no running the same water set up at the 260 no poppet valve or thermostats poppet plate fitted and dumps the water out the tray I have restrictors in the thermostats with a 6mm hole is this to small??