how fast should my boat run with this Merc?

[mkeleher]

I have a 1991 Norris craft that has a 1991 200hp EFI 2.5L merc on the back. I dont think it is running on all cylinders and am only getting 45mph. So the question is, how fast should this boat really go? From what I hear Norris craft's are meant to be fast similiar to a bullet bass boat. Attached is a pic of the boat

 

[wired247]

Re: how fast should my boat run with this Merc?

Depends on the prop. I'd expect to go at least 65 with a 21 pitch or steeper prop.

 

[Mi duckdown]

Re: how fast should my boat run with this Merc?

New boat to You? if you suspect it not running on all cylinders or dropping a cylinder check that out before doing anything.
On a side note how close to the road is that spare tire when towing. Why I say this is. God forbid your coupler comes of the ball and that tire hits the road, it will not be pretty for You or anyone near you on the road. Just My observation.???

 

[mkeleher]

Re: how fast should my boat run with this Merc?

About 1 1/2 ft from the ground. And yes the boat is new to me. Took it to the mechanic today to get it evaluated and he had all kinds of suspisions. One, the timing looked off, 2..the computer could be bad, 3..bad switch boxes...etc etc etc.. The list went on and on. Im worried that I might have gotten in too deep with this boat. First time to the lake the it would go about 45 mph. Took a while to get to that speed but it got there. Fished all day (slammed the fish I might add) start the motor up and it idles great. Go to put it in gear and it doesnt want to take off. Will only go about 5mph and not get on plane. Went to the boat ramp and checked the plugs. 2 were fouled out pretty good so I went and bought 6 new plugs. Went back to the lake yesterday, ran the boat and it got up to about 45 again but wouldnt get any more. What kind of suspisions do any of you have? Major part? Computer, loss of cylinder, could off timing be causing this? Compression was good by the way. Thanks for all the insight. Everyone on this forum seems to be very knowledgable.

 

[wired247]

Re: how fast should my boat run with this Merc?

Find a new mechanic. At first I wrote this skipping over that you have an EFI motor. The EFI computer seldom goes bad and if it does you'll know it as it won't be running at all. What usually goes wrong with outboards is they sit too long and the old gas gums up the jets in the carbs or injectors. They'll idle all day and sound great on the muffs as soon as you need to start passing some serious fuel through the gummed up carbs or injectors, they fall flat. You should be on plane in two seconds and going 60 in less than ten.

Check the spark and compression , adjust your timing, get the injectors professionally cleaned.

 

[mkeleher]

Re: how fast should my boat run with this Merc?

Had spark on all cylinders and compression was good (I checked that). I dont know if he was going to check the carbs out. When a mechanic works on a motor does a "Tune up" typically include the carbs cleaned? I know he was going to do a link and sync and check compression. When I talk to the mechanic tommorow I will ask if he checked out the carbs and injectors since it could be a potential problem. From the so of it wired247, it may not be an expensive fix since it would still run 45mph?

 

[wired247]

Re: how fast should my boat run with this Merc?

You have injectors. There is no link and sync or carburetors.

Compression, have the injectors cleaned.

 

[Faztbullet]

Re: how fast should my boat run with this Merc?

The EFI computer seldom goes bad and if it does you'll know it as it won't be running at all.

Going to disagree as they fail quite often and still run. Most common failure is fuel driver circuit and MAP sensor and the MAP will cause this type of problem. You could also have a failed TPI or fuel pump/pressure or fuel regulator problem along with what 247 posted about injectors dirty. I recommend they be pulled and flowed/balanced every 3 years as the filters in them can get clogged from debris over the years. If you think its a ECU or injector problems pull them and send to Tony at Brucatosvs.com and have cleaned and tested.

 

[mkeleher]

Re: how fast should my boat run with this Merc?

Found out the problem. The motor had the incorrect spark plugs. Guy at Autozone didnt match up the correct plugs that I had. Also the timing was way off. Thanks for all the good advice though

 

[mkeleher]

Re: how fast should my boat run with this Merc?

Onto the next issue. Took the boat out and it ran good for about 10 Minutes Wide open or until the motor heated up. Ran the motor about 50 MPH for 10 minutes and all of the sudden the motor just shut off. Tried to start it and it was flooded. I waited 5 minutes before starting again and it fired up. Thought it might have just been a loose connection. Well, decided I would turn around and head back to the landing. Ran it about 48 MPH and right before I got to the landing, boom motor shuts off again. Water pressure is good and the motor will always start back up, but as soon as it get hot enought it shuts off. There is no alarm that goes off or anything. Spoke to a local marine tech that lookd at my motor previously and he said it could be the stator and reactifier not cooresponding with each other and telling the computer to shut down. Guy that owned the boat before me had a used stator put on the motor which didnt exactly match the reactifier that was on the motor. So the next series of questions are 1. Could the stator be the culprit of the motor shutting down? 2. How can I make sure it is the reactifier and not stator or vice versa. Would had to throw money into a part and not be sure that is what it is