95 Mercury 200EFI 200XR OG321059

[HemiEd]

I have been reading everthing I can find on this motor and my head is spinning, lots of information and wisdom on this board. Thank you in advance for any help with my issues.

Bought the 95 Astro 21DCX about a month ago with just 101 hours on it. I received no manuals or history on the boat, but it was very obvious the hour meter was correct.

Lots of hours in it so far, but am confused on the motor symptoms.

On cold start, it starts right up, idles good and under throttle has tremendous power and response.

However, once you shut it off a while, for fishing, it is extremely difficult to start. You have to push the gear release button in and give it about half throttle. Once it finally starts firing a major smoke cloud is present. You have to be quick to get it in gear without dyeing. Then it runs excellent after "the cobbs are blown out"

Like I mentioned, no manuals and I have been trying to find some. Reading everything I can find on this motor. I had assumed the pressure gauge on the dash was oil pressure, but it is not labeled.

When servicing the motor (new plugs, compression check [125 in all], fuel filter/ws, lower end, water pump etc.) I took the motor oil tank cap off and oil started pouring out.

I did all of this prior to even trying to start the motor as I figured it had been sitting many years with only 101 hrs being 27 years old. (I bought the boat from a party that had taken it in on trade and knew zero about it or boats.)

My first thought was maybe an oil pressure relief valve or vent was not working properly?

Then, since the temp gauge never moves, I thought maybe the ecm was telling it to start too rich for a warm engine?

Thank you again for accepting me to this board and any advice you may offer.

[leonreno]

Pressure gauge is most likely water pressure. It is also recommended to pump the fuel bulb before each start, it helps reduce gas vapor in the lines and help ensure a good start. There are sensors that monitor motor temp that could be off, but that will be for others to help, I’m not super familiar with those systems. Also, I’m pretty sure you are missing one number in your serial number.

[HemiEd]

Pressure gauge is most likely water pressure. It is also recommended to pump the fuel bulb before each start, it helps reduce gas vapor in the lines and help ensure a good start. There are sensors that monitor motor temp that could be off, but that will be for others to help, I’m not super familiar with those systems. Also, I’m pretty sure you are missing one number in your serial number.

Thank you, I will double check that.

[HemiEd]

Pressure gauge is most likely water pressure. It is also recommended to pump the fuel bulb before each start, it helps reduce gas vapor in the lines and help ensure a good start. There are sensors that monitor motor temp that could be off, but that will be for others to help, I’m not super familiar with those systems. Also, I’m pretty sure you are missing one number in your serial number.

Yes sir, I is 0G321059, my mistake for thinking I could take it off the paperwork instead of cleaning off the plate on the motor swivel set up. I can't edit the opening post title.

[EuropeanAM]

Fixed the serial number for you.

Two areas I would look at:

-Fuel pressure test. Record results with key on, and while idling. Turn key off and record results at 15, 30 and 60 seconds after shutdown.

-Remote oil tank pressure: Run up the lake at least 5 minutes, find a quiet spot to shut down and fish (set a timer for 5 minutes). At 5 minutes, loosen the cap on the remote oil tank while listening carefully for pressure to escape. There should be NO PRESSURE at this point. *

* Also note that if the tank looks like it is swelled up (like a gas-can left sitting in the sun) this is an indication of a problem as well.

[HemiEd]

Fixed the serial number for you.

Two areas I would look at:

-Fuel pressure test. Record results with key on, and while idling. Turn key off and record results at 15, 30 and 60 seconds after shutdown.

-Remote oil tank pressure: Run up the lake at least 5 minutes, find a quiet spot to shut down and fish (set a timer for 5 minutes). At 5 minutes, loosen the cap on the remote oil tank while listening carefully for pressure to escape. There should be NO PRESSURE at this point. *

* Also note that if the tank looks like it is swelled up (like a gas-can left sitting in the sun) this is an indication of a problem as well.

Thank you very much! When you say remote oil tank, do you mean the one on the motor or the main one in the boat?

To be honest, removing the engine cover even standing in my shop is quite a task for this 72 year old man, I can't imagine trying to do it on the water. Would it be ok to do it with the mouse ears on a hose? I am fairly certain the tank on the engine is maintaining residual pressure and was curious if there is a relief valve or vent plugged up? I will run the test tomorrow, with the mouse ears and hose if you endorse that?

After reading so many of your posts, I have more confidence in you than taking it to a local shop. This is my 11th boat, but the only 2 cycle OB was a 97 40 hp Mariner with carbs.

I am going to have to procure a manual and do some more reading to perform a fuel pressure test.

[leonreno]

He wants you to open the remote tank, which is the tank on the boat not the motor. The tank on the boat is pressurized by the motor running through a check valve off crankcase pressure. The check valve is designed to slowly release pressure so the remote tank does not sit a long time with pressure which could push oil through the fuel system causing oil/smoke problems.

[HemiEd]

He wants you to open the remote tank, which is the tank on the boat not the motor. The tank on the boat is pressurized by the motor running through a check valve off crankcase pressure. The check valve is designed to slowly release pressure so the remote tank does not sit a long time with pressure which could push oil through the fuel system causing oil/smoke problems.

Thank you, that will not be a problem then. Certainly appreciate the help! Hopefully I can return the favor some day.

[HemiEd]

Thank you, that will not be a problem then. Certainly appreciate the help! Hopefully I can return the favor some day.

Well it rained all day, AGAIN, so I didn't get the boat out.

[HemiEd]

It has been some time and I need to update the situation with the boat, thank you to those that helped me.

1) I received manual I ordered and spent a lot of time studying it.
2) No pressure on the remote oil tank after running, that seems fine.Hh
3) I had taken the BU8H plugs out and replaced them with the OEM plugs, BPZHS10, turns out to be a mistake. .They were a bad $7 each investment. I cleaned the BU8H plugs up and put them back in.
4) When I got the boat, both tanks were empty. Made the mistake of putting in 87 octane gas with 10% ethanol. Got my electric fuel pump and pumped it all out of the tanks. It's good enough for the mower and my trucks.
5) Now, the boat runs great, starts right up and idles after sitting unlike before. The temp gauge works, but stays on the cool side.

Only real problem with the motor now is on occasion after puttering around at slow speeds it takes a bit to get up to rpm and power. I can live with that.

Thanks again for all the help.