02 2855 350 mpi saga continues.......-gctid392600

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So I confess..... I had 2 of the plug wires wrong... what a dummy!!

However I still have a lack of power.

This boat is new to me , I'll tell you what I'm experiencing, if another owner would please tell me if I'm expecting too much.

With a full tank of gas and water, three adults, and the usual assortment of weekend parafenalia it takes almost a full minute to get up on plane. Also, I have to keep full throttle to stay up on plane, and I'm doing a maximum of 4000 RPM.

I know a 350 is not a lot of power for the size of boat, but on our first trip it seemed to rock along pretty good.

Please let me know if I should expect a little better performance, right now my boat seems like a real dog!!

Chris

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Wally wrote:
So I confess..... I had 2 of the plug wires wrong... what an a..h..e!!

However I still have a lack of power.

This boat is new to me , I'll tell you what I'm experiencing, if another owner would please tell me if I'm expecting too much.

With a full tank of gas and water, three adults, and the usual assortment of weekend parafenalia it takes almost a full minute to get up on plane. Also, I have to keep full throttle to stay up on plane, and I'm doing a maximum of 4000 RPM.

I know a 350 is not a lot of power for the size of boat, but on our first trip it seemed to rock along pretty good.

Please let me know if I should expect a little better performance, right now my boat seems like a real dog!!

Chris

Hmm....That dosen't sound right to me at all. I have the same model, year and engine. Here is what I do..... I throttle up gradudally until the needle reads about 3000 rpm, she gradually comes up on plane. I don't know how long but not a minute. As she reaches plane the rpms will come up until she is at about 3800. I then back off a little and run at 3500. Max rpm is at around 4600. Even with 5 adults on board, I've never had to run at full throttle to stay up

There are so many factors that affect performacne....how is your bottom? your props?

[TenMile Guru Find all posts View Profile Close TenMile]

I've got a 5.7L in a 288 which is the same size and it gets it up on plane just fine. Had it out last weekend with 6 adults and 2 kids plus a full tank of fuel. Had to use the trim tabs to get up, but it didn't take any more than about 20 seconds.

Couple of things -- one is that WOT is 4800-5000 RPMs with that engine so it sounds like you could be over-propped. That would explain the slowness out of the hole and your inability to hit higher RPMs. With that boat, you should probably be swinging a 19p prop (assuming you have a Bravo III).

Second, in the other thread you started, you mention that when you turn the key on you hear two beeps? That may be the sign of an engine fault although most faults will have the warning horn going non-stop. The normal sound is one long beep that lasts about 2 seconds. When your mechanic checked out the engine, did he put the diagnosis tool on the ECU to see if the engine is throwing any codes?

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It does sound like it could be over-propped, but why would someone go through the expense of swapping out two very expensive stainless props to the wrong ones? (on a boat that is only 10 years old) I have the same year boat and i have whatever the factory recommendation was I guess.

Couple of things -- one is that WOT is 4800-5000 RPMs with that engine

Sometime after 02 they may have changed their minds about max rpm. My Merc-cruiser manual that came with my new then 02 boat says max rpm should be 4600 - 5000. I'm at the lower end of that spectrum.

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I agree -- pretty expensive if it's just a guess. However, I did have my Merc guy go to the book a short time ago on my 288 to check on the proper prop pitch. If your leg is a 2.0:1 ratio (this is the typical configuration) pitch will likely be recommended as a 19p. If it's a 2.1:1 ratio then the pitch recommended is a 20p.

My last boat had the 5.7L but someone had put a 24p prop on it. Same thing -- very slow out of the hole, and WOT was 3800 RPMs. Went right down to a 19p prop and it was like I owned a new boat. RPMs went up -- responsiveness out of the hole went up, fuel economy increased and top end increased -- it was amazing. You could even hear it in the engine.

Anyhow, just going from the stuff that's been provided so far so I'd be looking at your prop -- the pitch number is easy to see as it's stamped right onto the sides of the props. If they are higher than 20p (e.g. 22 or 24p) I'd be looking to swap them out. If you do swap them, Merc has a new 4 blade inner, 3 blade outer that costs less, and handles better at slower speeds.

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Thank you all for your ideas

We brought the boat home 200 miles on the water and Im sure the preformance was not like I am experiencing now, so I don't think it's the props, but I will check the pitch.

Bottom is freshly painted, props are good as new...

My batteries are not too healthy, and I've been holding off replacing them untill getting the mechnical sorted out, only so I'm not doing too many things at once, but I wonder if failing batteries could be part of the problem??

If the batteries are compromised could this affect the preformance??

If there is low voltage maybe the fuel pump isn't able to deliver as it should.

What do you guys think??

As for the mechanic, he did not scan the engine so am unsure re: codes

And yes the alarm certainly emits two maybe half second beeps when keyed, oil pressure and temp appear ok.

I'm going to start with the batteries, since they need to go, but please let me know what you think.....

Regards,

Chris

(frustrated in Courtenay ??)

[TenMile Guru Find all posts View Profile Close TenMile]

So yes, if you were able to achieve WOT before -- and performance was as it should be, then rule out props.

Other possibility is that you've got a bad or plugged injector so a cylinder maybe isn't firing. One way to test this is to start the boat and get the RPMs up to about 1500 RPMs. You can then unplug the injector connections at the top of each cylinder one at a time. You should hear the boat run rough when you unplug each injector. If it doesn't sound any different, it may be a sign of a dirty or bad injector.

Don't think this is a battery issue. If your battery was that bad, it wouldn't start the boat and you'd be getting low voltage alarms and the engine guardian would kick in. Certainly isn't going to hurt anything replacing them if they need it....but don't think you'll find the problem there.

[Chief_Alen Guru Find all posts View Profile Close Chief_Alen]

This is a generic list you don't have a carb: for example.

Engine Won't Reach Operating RPM. Check

1. Fuel condition. Type and Octane possibly old fuel

2. Propeller pitch or diameter, damaged blades

3. Restricted fuel pickup tube or anti siphon valve Fuel System Test

4. Crankcase oil volume, high oil level can cause aerated oil and lifter collapse

5. Marine growth on hull and outdrive

6. Wrong gear ratio in outdrive

7. Restricted carburetor air intake (clogged flame arrestor)

8. Restricted exhaust system (broken exhaust shutters/flappers) in engine transom shield or drive

9. Poor cylinder compression Compression Test

10. Carburetor defective, or wrong type.

11. Fuel pump pressure and vacuum

12. Boat overloaded, improperly loaded, or improperly trimmed.

13. Engine Overheating

14. Engine timing and ignition system operation

15. Remote control cables and linkage for proper travel to open throttle plates fully.

Above copied and pasted from another website Don s is the author.

Added by Chief Alen

16-Valves need adjusting.

If anyone else want to add to the list now would be the time i am saving it for re-post to other questions such as this.

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I agree with Terry, I'm pretty sure this can't be caused by low batteries and you can rule out a prop problem as well if you were getting proper performance before.

I would not however rule out condition of the bottom and outdrive. I've seen growth happen in two weeks time that drastically affected the performance of my boat which had been bottom painted at the beginning of the season

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Proceding with swapping out the batteries.

Have ruled out most of the items on Chief Alen's list, will work on the rest.

Trying to find a mechanic with the ability to read codes, and will try pulling the injector wires.

All this should take me to the weekend..... work gets in the way of fun.

Hey Terry, there are two plugs on each injector, do I pull them both or should just one do the trick?

Chris

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It's the electrical you pull on the injector. It's a flat waterproof plug that unclips and pulls out.

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Got a clever mechanic who figured out the problem in 12 minutes, and had it fixed an hour later.

There is a circlip inside the distributor cap under the rotor that holds the shaft. The circlip was MIA, and so the shaft was moving up and down causing the timing to go out of wack..... I don't know how she even ran.

After installing a new clip, and adjusting the timing she purrs like a kitten,and of course everything else is done since I gave her a great tune up looking for the problem!!

Thanks to everyone for their comments and suggestions.

Bring on the Canada Day long weekend, and hopefully some summer weather!!!

Chris