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Author Topic:   Problems with 1995 225 Mercury
dcwhaler posted 07-23-2004 04:42 PM ET (US)   Profile for dcwhaler   Send Email to dcwhaler  
I bought a used 1997 23 Conquest with a 1995 225 Mercury this spring. Had problems with it overheating after I bought it from a dealer on Long Island. Now the oil light and buzzer are coming on when I start it. Anyone have an idea what could be wrong? Have recently have the engine checked for the overheating problems, not the oil light problem. Thanks for any advice.
LHG posted 07-23-2004 06:25 PM ET (US)     Profile for LHG    
Have never heard of an "oil Light" and "buzzer" on a Mercury 2-stroke V-6.

Give us a more accurate description of your symtoms and signals.

tuna1 posted 07-23-2004 06:39 PM ET (US)     Profile for tuna1  Send Email to tuna1     
Yes, oil light and horn, part of the automatic oil injection safety system.The problem is with the oil pump system. Most likely the plastic crankshaft gear of the oil pump system is stripped.

How handed are you, do you want to do this yourself?? Do not run the engine unless you premix oil to gas tank as a safety precaution so you won't run it on no oil.If the crankshaft gear is gone, you will not be oiling the powerhead and this is what the alarm system is warning you about!!!!

dcwhaler posted 07-24-2004 10:24 AM ET (US)     Profile for dcwhaler  Send Email to dcwhaler     
The light that is coming on is on the control panel and every five minutes or so an alarm will go off. This is proably something I can't fix. I am just a bit miffed that ever since I bought the boat that I have had problems with the engine, bought it used from a Whaler dealer and trusted that everything was ok. Am thinking now about re-powering it with a Honda 225, something I was planning on doing in the future anyway since I had re-powered my former boat, a Montauk with a Honda and had very few problems.
Clark Roberts posted 07-24-2004 04:49 PM ET (US)     Profile for Clark Roberts  Send Email to Clark Roberts     
DC, the only oil alarm that I know off on a V6 Merc is a low level alarm for the under cowling "ready" tank. This is the small tank that gravity feeds the oil pump and is kept full via the pressurized remote (3 gal) tank. Now, if the ready tank comes off full any amount the alarm sounds and procedure is to check the level in the ready tank visually and if not completely full then check the remote tank for quantity and pressure (both fill cap and the press/delivery cap with the two hoses must be tight for oil to be delivered to ready tank). If remote tank has oil and press and the oil lines to engine are connected properly then you can refill (top off) the ready tank by starting the engine and loosening the cap on the ready tank...oil will flow into tank (pushing the air out) and at the point of overflow tighten cap. Bingo ready tank is full! Now if alarm still sounds then the level sensor in ready is suspect. You can disconnect the blue wires from sensor, thus silencing alarm and mix oil in gas tank for good measure and run a length of time so that you can determing oil level decreasing in remote tank (make marks or use tape to mark level...etc.). Reduction in oil level will verify that oiling system is ok and that level sensor is bad and you can replace it yourself as it is in the cap I believe. I have never heard of anyone having any serious problems with a 225 EFI Mercury or the Mercury oiling system. I would not give up on it unless you want a justification for getting a Honda. In any case you should fix Mercury to increase its value... why am I going through the obvious... blah, blah, blah... happy Whalin'... Clark... Spruce Creek Navy
pashopper posted 07-24-2004 06:24 PM ET (US)     Profile for pashopper  Send Email to pashopper     
Try this thread on the merc 225 EFI. It discusses the Poppet valve problems. May not be your issue but it is common on 96,97, 98 merc 225 EFIs.

jimh posted 07-26-2004 06:03 AM ET (US)     Profile for jimh  Send Email to jimh     
What I find odd here is the motor is two years older than the boat. Usually it is just the opposite: the boat is older than the motor.

A nine-year-old motor that has been running in salt water all its life is a good candidate for cooling system problems, no matter what brand.

If the engine alarm is sounding, it is trying to tell you something. Often the cadence of the alarm is significant. Check the owner's manual to see what the signal is intended to mean.

It is also curious that your engine has warning lights and others don't seem to have them. Can someone explain that situation? I have been a few boats with Mercury engines from this era, and I don't recall a light annunciator panel as part of the standard installation of engine controls.

bsmotril posted 07-26-2004 09:06 AM ET (US)     Profile for bsmotril  Send Email to bsmotril     
The 1997 Optis have an alarm gauge with 4 indicator lights; Temp, Oil, Water in fuel, and engine fault. Low Oil in the under cowl tank will give you 4 beeps from the horn, off for 2 min, and repeat. The Oil light comes ON the gauge, and no reduction in engine speed. NO Oil flow gives a continuous horn, oil light =ON, and engine RPM limited to 3000 or less. There are two ECM sensor inputs for oil: 1) There is the float sensor in the under cowl tank. 2) There is a flow sensor built into the oil pump.

I have replace float sensors on Three mercs I have owned after 4-6 yrs of operation, they seem to be a common failure item. it is an easy do it yourself fix. Never had a flow sensor fail on my Optis. One thing you can do is force a reprime of the oil pump which will eliminate air in the lines. You do this by putting the key in the run position and actuating the throttle interrupter switch 5 times in succession. That is done by shifting from neutral to forward and back.

Also, the oil pump is electric on the Optis, and not crankshaft driven. Low battery voltage will cause various faults and problems with the oil system. If you see problems mainly at idle where alternator output is low, don't overlook a possible problem with the battery or loose cables.

jimh posted 07-26-2004 09:30 AM ET (US)     Profile for jimh  Send Email to jimh     
Bill--Thanks for the excellent article, but I wonder if the 1997 Optimax and its alarm system is the same as a 1995 EFI?

Also, if that 225-EFI has been pushing the 23 CONQUEST around all its life by itself, I can feel its pain. That is a 3750 pound hull, and with a motor, fuel, gear, and crew, that boat probably comes in over 5,500 pounds.

bsmotril posted 07-26-2004 02:05 PM ET (US)     Profile for bsmotril  Send Email to bsmotril     
Sorry, Jim, I missed the EFI reference in the thread. The Opti and EFI are certainly different. What I stated does not apply to the EFI Merc other than them using the same float sensor for the under-cowl oil tank. BillS
dcwhaler posted 07-26-2004 05:39 PM ET (US)     Profile for dcwhaler  Send Email to dcwhaler     
The overheating problem seemed to be connected to the long shaft on this engine, all parts had to be perfect in order to get the water up to the head. The dealer I am working with down here has told me the Mercury rep. said to run the engine at a high initial rpm at idle to make sure water got up to the top of the engine. Have not been able to try that since the oil light and buzzer have gone off on the dash. Will try the ideas you guys have given me before I give up. Thanks for all the help.
jimh posted 07-26-2004 07:55 PM ET (US)     Profile for jimh  Send Email to jimh     
Now that is an interesting point, and one I don't recall anyone mentioning previously. The CONQUEST 23 needs a 30-inch shaft if rigged with a single engine. So we have to assume that this boat has a XXL Shaft Mercury 225 EFI.

Moving everything six inches higher in the cooling system could put an additional strain on the pump to get water all the way to the top.

Also, how the engine is trimmed could affect the cooling. If you have the engine trimmed up quite a ways, it could move the water intakes into more aerated water. This would reduce the cooling.

bsmotril posted 07-27-2004 12:49 PM ET (US)     Profile for bsmotril  Send Email to bsmotril     
I don't think the longer shaft would matter from the perspective of the work the pump has to do. That powerhead is still about the same distance above sea level with a long shaft as twin short shafts would be, so the head pressure the pump has to overcome should be the same. True, turbulence and aeration are more likley with a single long shaft engine and it would be more sensitive to trim angle. BillS
dcwhaler posted 07-27-2004 06:05 PM ET (US)     Profile for dcwhaler  Send Email to dcwhaler     
Thanks for the help on the engine oil problem. I loosened the top of the tank next to the engine, it filled with oil, problem solved. OK, now on to the other problem I had have with this engine since I bought it. When the dealer took me for a test ride the engine overheat warning buzzer went off and the the guage showed the heat at 3/4. The dealer put new themostats in and replaced the water pump, I brought it home and took it out thinking the problems were solved. The first time I took it out the engine did not overheat at idle but as soon as I put the boat up on plane at about 4000 rpm the guage went up to 3/4, the alarm went off and the engine throttled back. I had a dealer look at it down here who tightened some things up but could find no real problems. Took it out again, engine did not overheat at first but did after about a half hour. Docked and told dealer about problem when he told me about the apparent solution of running it high at idle to get water to the top of the engine. Could not do that because of oil problem. Solved that today and took the boat out. Started the engine and let if run at hign idle 2500 rpm for several minutes, took boat out of harbor, running at about 1200 rpm, for about 10 minutes. Took the boat up on plane at 4500 RPM and watched the temp. guage slowly move up to 3/4 and the alarm went off. Put it neutral and ran at 2500 rpm and it cooled down to 1/4 on the guage. Tried this several times, changing the engine trim. OK, now are there any easy solutions you gusy can think of? Thanks again for the help.
Clark Roberts posted 07-28-2004 07:55 AM ET (US)     Profile for Clark Roberts  Send Email to Clark Roberts     
DC, strange that the mechanics did not top off the ready tank as std. proceedure on the oil alarm! Glad you know the drill now but still the question is "why did level drop in ready tank?". Be sure to check that both caps on the remote tank are tight as this is necessary for oil to flow to ready tank. If ready tank remains full, however, then everything is ok. Now that overtemp problem...engine should cool at speed due to press of moving water even if water pump isn't functioning. However if there is a blockage/restriction somewhere in the cooling water circuit then overheat would occur at speed. Here are some things to check: blockage in pump housing (an old pump vane, debris etc);blockage of intake holes (the vertical holes in lower unti); blockage in "up" tube (take lower unit off and run water from tap through tube... cut off a water hose and clamp onto tube);blockage in engine block; remove thermostats and see if that makes a difference... change to 120 degree thermostats; install a Quicksilver water press gauge, per instructions tapped to crossover tube) and check that there is proper water press at idle (about 5 psi) and at speed (about 15psi). These pressures are a guess on my part but important thing is to see the press increase as engine speed increases. If water press is suspect then there could be a blockage/malfuction in cooling system or engine is mounted too high. If engine is mounted up then try lowering a hole and see what happens. I once cleaned out a badly corroded engine's cooling system by running it in a barrel with about 50% mixture of water and vinegar... ran it for about 8 hours and upon subsequent removal of exhaust baffle found that inside of cooling passages were clean as a whistle. This was back in about 1953 when I was 16 and the motor was a 7 1/2hp Wizard (Western Auto's brand)given to me because it was no good. My mom told me to try the vinegar! I ran the engine for a long time after that... this is getting to be a long story so will quit! Happy Whalin'... Clark... Spruce Creek Navy
bsmotril posted 07-28-2004 09:28 AM ET (US)     Profile for bsmotril  Send Email to bsmotril     
This sure sounds like the poppet valve problem. When that valve is working correctly, you can watch the temp gauge climb to about 3/4 at high idle speed. At around 2500 rpm when water pressure builds, the gauge will drop rapidly down to 1/4 when the valve opens up, and the temp will stay down there up to WOT. Your new water pump eliminated that as a problem source, leaving other things to look for. Other than poppet valve, the other possibility is some kind of blockage in the cooling passages. Pulling the heads off and checking the water jackets is called for there. With a motor that old used in salt, replacing the head gaskets is not a bad idea anyway. Because it is easier to replace or clean the poppet valve assembly than it is to pull the heads, I would look at the valve next. Not sure about the big blocks, but with the small block V6s, you have to remove the lower engine cowl to get to the valve assembly. Problems like this are a process of elimination. With a used motor of unknown history, replacing these components as you go through the elimination process leads to peace of mind and confidence in your power plant.
Swellmonster posted 08-04-2004 10:52 PM ET (US)     Profile for Swellmonster  Send Email to Swellmonster     
Does a motor have weak water circulation if the tell tale pipe has strong pressure?
bsmotril posted 08-05-2004 10:34 AM ET (US)     Profile for bsmotril  Send Email to bsmotril     
The telltale is only good for determining if there is any flow at all. To really troubleshoot the system, you need a water pressure gauge installed. My first sign of the pumps needing replacement is temp alarms going off even though the telltale is strong and the temp gauge reads halfway. Replace the pump, and no more alarms even though there is no visible or tactile change to the telltale flow. BillS

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