Mercury 225 Offshore

[Fletch170]

Hey guys,

Bought my first black motor! I've always been a Yami guy, and this is my first trip to the dark side.

its a 1996 (I believe), Carb model. I like it because I can work on it. From the research I've done, these motors are thirsty and smoke a bit......but besides that, very reliable and as cliche as it is to say "Bulletproof".

I plan on doing the garden variety stuff like plugs, thermostats, and water pump. IS there anything else I should just replace while I'm at it? I was told to check the VRO pump and stator.

Any advice would be greatly appreciated.

-Fletch

[wingtime]

There is no VRO on a black motor!    They have a separate mechanically driven variable rate oil pump.  There is a check valve on the starboard side of the motor that supplies crankcase pressure to the remote oil tank.  That pressurizes the tank forcing oil from the remote tank to the header tank under the cowl.  The oil pump then mixes the oil from the header tank with the fuel through a fitting on the fuel pump.  The alarm will wound if the oil level in the header tank is low or if the shaft that drives the oil pump stops turning.  Make sure you get a self test beep when you first turn on your key.

I'd service the following on a Merc:  Fuel pump,fuel filter, T-stats, water pump, poppet valve.  Cleaning the carbs is another option.

[Blue Agave]

Congrats!  Once you go Black, you'll never go back.

Wingtime's list is a good one, I would recommend new plug wires as well.

[fitz73222]

Excellent advice Bruce; that's exactly what I would do if it was mine and do a baseline compression test. If the engine hours are unknown I would still install an hour meter to establish a maintenance baseline for future reference. It was a very stout 3.0 liter block. Prop it right at the upper half of the recommended full throttle rpms and you're good to go. If you are looking for the right prop I love Stilletto props and they're reasonably priced in the $400-$500 range. 1996 had the ignition upgrades as far as the stator and related components. I also strongly recommend a decoke of the engine using the spray type engine tuner from Mercury (Power tune), ValveTec or even the BRP (OMC) or Yamaha variant; all the same chemistry.It will drasically reduce idle smoking, improve running quality and help bottom end torque. It's my standard 100 hour PM service interval. Assuming the engine has had reasonable care you're going to like this engine.

[wingtime]

Farley,

Not to derail but since you are on the subject of decarbing...   I was planning on decarbing my 225 Ocean Pro this weekend using the Seafoam method.  Whats you input on that method VS the spray products?

[fitz73222]

Hey Bruce,
I've never used it before. Everything I've read on other engine forums is that it works but I have no personal experience with it so I can't endorse it. I've used the other treatment method for over 30 years so it is what I can speak too.

[dburr]

Bruce are you using the spray Seafoam?  Just curious..  I did the storage treatment last fall with a full tank (70 gal) and 2 cans of Seafoam and have been doing the Seafoam gas treatment this season and no rough running on the OX66 at all.  

I was looking at the Seafoam spray stuff and DeepCreep for another motor..  Their instructions were almost identical to what Farley said in another thread..  I ended up going with DeepCreep 'casue I mistakenly thought it was on Farley's list ..

[wingtime]

yeah I know the deep creep is just Seafoam in an aerosol form.  I was going to do the Seafoam mixed with a gallon or so of gas.  You get the motor up to temp.  Then you hook up a gallon gas can with Seafoam added to it...  run it on that for 15min.  Let it sit and soak for 15... then run it again...  soak  then run again...   And you smoke the neighborhood out!

[fitz73222]

Just make sure when you do this pickling process don't breathe this . She's going to smoke and belch all kinds of oil tadpoles and soot. Set a fan up behind you or wait till the wind is blowing away from you towards the squatters or undesirable neighbors! Most of this stuff is naptha based and plays hell on your lungs. If you read the can precautions you'll understand.

[wingtime]

Thanks..  I didn't get a chance to do it today.  While towing the 245 home from my office I stopped for some fuel.  When I was turning into the gas station I noticed my left rear trailer tire was flat!  I found a piece of aluminum protruding from the edge of the tread!  Just what I wanted to do.. swap out tires when the heat index is 100.

[slvrlng]

Speaking of de-carb. We went out the Sunday before Labor Day out of Innerrarity point just to the west of Pensacola pass. After slow trolling for a few hours then running back to the ramp, when I went to put it back on the trailer there was a bunch of sea grass around the ramp. Evidently I sucked some up while trying to power up the trailer. This ended up causing the motor to overheat and in that process I fouled some of the plugs. Got the boat back to the house and Flounderpounder came over the next day to help me diagnose what all was going on. I was a little low with compression on two cylinders and it had a miss at idle. Went and had a fine Labor day bar-b-que at Marcs and next day did the seafoam mixed with 3/4 gallon of gas. If you search for "Dunk's decarb" you can find the info on quite a few threads. If you use this I feel it is fairly important to keep the one can of Seafoam to 3/4 gal gas ratio. I mixed it together and pulled the line from the filter and stuck it in the tank, pumped the bulb and fired her up. After about a minute of running  here came the smoke and boy does it smoke! Thank god the wind was blowing down the middle of the street! I ran it 10 minutes and then shut it off and let it sit for 15 minutes. I did this routine four times until the gas Seafoam mix was gone then re attached the fuel line to the filter. At this time a huge thunderstorm blew up at the house so I did not get to run it until the next morning. Put in at the ramp by my friends house and ran the piss out of it on the old plugs. With the old plugs I could only get 5000 at about 39.5 mph on gps. Ran back to the ramp and put new plugs in. Then with myself and Bridget I could get 5400 rpms and 44.7 mph on gps. It also ran much smoother at idle and had much more torque coming out of the hole. I have not checked the compression yet as we fished in a tournament for the next three days and just got back to ATL last night.

Oh by the way we came in third in the tournament and yes there were more than 3 boats in it! Not many more but more than 3 LOLOLOLOL!!!!

[Fletch170]

Is it worth replacing the oil pump gear? How difficult is this? I don't want to be 30 miles out and have that thing fail.

I will be doing the decoke for sure....anything to help this old girl run like new.

The lower unit had new seals installed, which is a good thing....assuming the gears werent destroyed by sea water already.....

Here is the listing for the motor, you can see the thing has PERFECT compression, and is very clean under the cowl. The exterior is a little rough, I plan on repainting the motor and adding some modern merc decals.

[wingtime]

The oil pump drive gear is a two piece split plastic gear that is wrapped around the crank shaft.  The only way to replace it is tear down the motor.  I heard that on newer motors some of them might be metal but I'm not sure if that is true or not.  The oil injection system is pretty simple and reliable.  You do hear horror stories of the plastic gear stripping and burning up the motor.  I would say that most likely happens to neglected motors that have been sitting etc and the oil pump or seals are tight or something from sitting.  As long as your alarm system is working then your OK.  The oil injection can be removed and you can go to premix if that makes you feel warm and fuzzy inside.  But you'll use more oil, possibly foul the plugs yadda yadda.  

If you are uncertain the oil system is working you can easily add some oil to the fuel (just to be safe), mark the oil level on the remote tank with tape, and then use the boat for a while.  If the oil level drops you know it's working.

[Fletch170]

Wingtime,

I agree with you. I'm sorry if I offend anyone here, but I look at premix as a lazy way out. I know VRO people who premix, but I also know people who do their maint and makes sure the system is working properly.

I just dont like the smokey premix idle, and the chance of blowing the thing to pieces on the top end. Is this all opinnion? yes. But that is just me.

Just to be clear, if the gear stops turning, the alarm will sound?

Kind regards,

-Christian

[wingtime]

Yes if the drive stops turning the alarm will sound.

I wouldn't say premixing is lazy. Some people just don't trust the oil injection systems. Also if something fails such as an alarm module or the drive gear the repair costs can be very high. Why spend that much on an older motor? Lets put it this way, Mercury sells an oil injection pump block off plug for a reason.