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beauford54

Do I Have a Problem with my 2003 215 SS??

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Hey Guys,

This is only my 2nd year with my '03 215 SS, so I'm not that experienced with the boat or boating in general. It seems to me that the boat is running ok, but when discussing a trip I took across the lake, my buddy was floored when I told him my boat (which has a 305 Mercruiser 5.0 engine with a 19" pitch 3 blade aluminum prop) tops out at about 39 MPH @ 4300 RPM's. That is with a half tank of gas, just me on it, and "properly" trimmed (trimmed up just below the point where it porposes if I trim it up more). I also mentioned I cruise at about 3300 RPM's with my wife and young kids on the boat and go about 29 on the GPS. He told me I have something major wrong.

So I searched the forums here and noticed other guys with 215's are going much faster! So is there something wrong with mine? I had it looked at by my marina this year and they gave it a tune up among a couple other things and didn't say there was anything wrong other than it only maxed out at 4000 RPM's. So he changed the 20" pitch prop to a 19 " and said that should do the trick.

So is there something wrong with my boat? Please help! And please keep in mind that I'm not mechanically inclined. Thanks guys!!

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Sounds like you're engine is down a cylinder, or the hull bottom is extremely dirty.

Is your engine fuel injected (5.0L MPI) or carb'd? 5.0L

Irregardless, you want to have the boat looked at. If fuel injected, I would start with the distributor cap and rotor, and then change out the spark plugs.

If you're looking to install a new cap and rotor for a MY 2003 5.0L carb'd engine, MerCruiser part # 805759T3 or Quicksilver part # 805759Q3 is the cap & rotor kit. Biggest problem with that ignition was the ignition sensor* under the rotor. Cause the engine either not to start, or to run rough. (engine won't start being the more common in our experience) New MerCruiser sensor design part # 87-892150K02 or Quicksilver part # 87-892150Q02 came out around 2005, and is much more reliable and robust. Thunderbolt ignition came out around '87, and is still used today on MerCruiser V6 and small block V8 carb'd engines.

8 of NGK BPR6EFS spark plugs.

MerCruiser 5.0L MPI

If you have a MerCruiser 5.0L MPI fuel injected engine, cap & rotor kit for HVS type (flat V8 cap style) MerCruiser part # 8M0061335. Have seen issues with AC-Delco spark plugs - I hate them. I highly recommend NGK Laser Iridium ITR4A15 spark plugs for the MPI version.

Delco HVS type distributor (flat cap style) Doesn't show 8M0061335 in the link below, but probably the cheapest way to get both the cap and rotor. If you see black paint overspray on your cap, it's original, which I hope is not the case. Original style caps had aluminum terminals vs. brass, which was a terrible idea regarding longevity.

http://www.marinepar.../884717/8093-50

On the HVS style cap and rotor, you'll need both a Torx T20 and T15 driver. On the cap hold-down Torx screws, loosen, tighten, loosen, tighten, then loosen all the way to help avoid wrecking the cheap POS plastic distributor. Cheap design, not cheap to replace if you break the 'ears' off that hold the distributor cap hold-down screws. Try not to lose the screws down into the bilge either. When replacing the cap, please just do one wire at a time from the old distributor cap to the new cap.

If a tune-up doesn't work, than I would clean the hull. If that doesn't work, and you have the MPI engine, I think I would then perform a compression test. If you have suffered a cap failure, 2 cylinders (3 & 5, or 5 & 7) may not have fired properly, resulting in those cylinders being washed out with raw fuel. At idle, the engine would appear to run properly, but have an odd exhaust note that you may not be able to hear.

I urge you to get the boat looked at in short order.

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+1 on advice above from Shep.

I cant tell from the picture but if the boat sits in the water at a slip all season you could have significant bottom growth that can easily take 10mph off top end speed.

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Hey Guys,

Thanks so much for the quick response. Shepard, it is a thunderbold V carbed engine and I've put a pic of the specs at the end of this message. The cap, rotor and plugs were all replaced this year. It does seem to make it run a little smoother than last year, but I've had the same performance for the past 2 years with the boat.

IndyChap, I do keep my boat in a slip all year. When I bought it 2 years ago I got it from a guy who ran it in saltwater and had bottom painted it. I only run it in freshwater, but the bottom paint was chipping off pretty good last year, so I had the marina touch it up. So it has a good looking coat of bottom paint on it and is clear of growth. However, is there a chance the bottom paint is causing the reduced performance? Should I have it stripped off?

Thanks so much guys! Since I'm in central NY, our boating season is almost over. I'm still happy to take it to another marina to have them check it out before the summer is over, just want to know what I should tell them.

Here is a pic:

EngineInfo.jpg

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Try MerCruiser part # 87-892150K02 or Q02. New style ignition sensor that goes under the rotor in the distributor. Came out in 2005 or so, and is a superior piece vs. the older stye ignition sensors.

No one has messed with the timing by chance? That engine takes a special timing procedure to get it into (and out of) base timing mode. One other thing to look at is verifying the actual MPH the boat gets with a GPS or smart phone, etc. That boat should get right around 47 MPH with that engine for your elevation.

One other thing to look at is the spark plug wires. Verify whether they're each on the correct spark plugs. NOTE: on your cap, you will notice numbers in a large font, and numbers in a small font. Ignore the small font numbers; only pay attention to the large numbers and where their wires go for each cylinder.

firingorder.gif

NOTE: if you ever need the engine serial number, you'll find a plate just above the starter motor. Probably start with an '0M......'

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Thanks, Shepard. I'm not sure if anyone has messed with the timing. I'll get it looked at along with the ignition sensor. I'm only getting 39 MPH on the GPS, so something has to be done.

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