2003 Maxum 2700 can't get on plane - Maxum Boat Owners Club

golfwins · 07-22-2019, 04:45 PM

Hello Everyone. Potential new owner here. I'm looking to purchase a 2003 Maxum 2700 with the 350 Mag MPI engine. The boat runs about 12-14 MPHs, but will not get on plane. In neutral the engine seems to rev fine. Under load we have heard the occasional backfire. Fuel pressure is about 37 at idle and about 40 WOT.

I replaced the fuel/water filter with not much if any improvement. Could these signs point to the TPS sensor, spark plus/wires/distributor, Fuel pump, injectors, or risers? Do you think I can rule any of those out?

I'm going to do a compression test today or tomorrow. Maybe a leak down test too. I need to make a decision soon, I really appreciate your help.

Jeremy

golfwins · 07-22-2019, 05:19 PM

I'll add that at WOT, the boat is showing about 3600 RPMs. It revs about that in Neutral.

mmwjr · 07-22-2019, 05:26 PM

Welcome aboard

Has the boat been stored in the water? If so the bottom may have marine growth.

I'm assuming it has a Bravo 3 drive; have you looked at the props for damage?

golfwins · 07-22-2019, 05:35 PM

Thank you for the response. It is stored in water and has not been used much at all. It's funny you mention marine growth. The owner did schedule it to be cleaned today. This will be my first slipped boat. Could that be all it really is?

Yes, it does have the bravo 3 and the prop seemed to spin freely by hand. It's rough to the touch due to growth so I need to give that a good cleaning. I'm not sure if that's is included in the bottom cleaning that is scheduled today.

One reason i didn't think it was just the bottom growth is due to the fact that it wouldn't go above 3600 RPMs. It seems to bog down at that point. I don't have a shop manual for this boat. I have the Mercury Manual 24 for my existing boat, but I think that's too early for this boat.

mmwjr · 07-22-2019, 05:44 PM

Quote:

Originally Posted by golfwins

Thank you for the response. It is stored in water and has not been used much at all. It's funny you mention marine growth. The owner did schedule it to be cleaned today. This will be my first slipped boat. Could that be all it really is?

Yes, it does have the bravo 3 and the prop seemed to spin freely by hand. It's rough to the touch due to growth so I need to give that a good cleaning. I'm not sure if that's is included in the bottom cleaning that is scheduled today.

One reason i didn't think it was just the bottom growth is due to the fact that it wouldn't go above 3600 RPMs. It seems to bog down at that point. I don't have a shop manual for this boat. I have the Mercury Manual 24 for my existing boat, but I think that's too early for this boat.

Yes marine growth can greatly impact performance. The growth will put a load on the engine limiting rpm.

golfwins · 07-22-2019, 06:00 PM

Okay, I hope that's all it is. I'll go test drive the boat after work today after it's been cleaned and report back. Do you happen to know which mercury service manual I need for this boat?

mmwjr · 07-23-2019, 01:53 AM

Quote:

Originally Posted by golfwins

Okay, I hope that's all it is. I'll go test drive the boat after work today after it's been cleaned and report back. Do you happen to know which mercury service manual I need for this boat?

#24 for the engine and #11 for the drive. Both can be found under Documents of this site.

golfwins · 07-23-2019, 03:58 AM

Thanks for the manual info. The bottom was cleaned today. The good news is that I was able to get it on plane. The bad news is that the engine still seems under powered. It starts to bog down at around 3000 RPMs. After 1-2 minutes of WOT, it finally got on plane and was running about 25 MPHs @ 4100RPMs.

So, I'm guessing there there is more to the story. Either fuel related or spark related. I thought about the throttle position sensor also.

I'm going to perform a compression and leak down test tomorrow and hopefully that will show that the cylinders and valves are good. Let me know if you have any other ideas.

jrsick · 07-23-2019, 12:14 PM

The Thunderbolt V ignition test on pg 1C-9 is excellent for locating ignition problems. Coil resistance values are located on pg 4B-4. Also see troubleshooting guide on page 1C-16 "Engine runs poorly at high rpm". Let us know if you need any assistance.

mmwjr · 07-23-2019, 12:35 PM

Since the boat was not used much and therefore probably not maintained well I would first address the old fuel. A quick check is to run on a portable tank with fresh gas, if this resolves the issue have the tank pumped and new gas put in.

golfwins · 07-24-2019, 02:59 PM

I decided to buy the boat yesterday. I'm having it delivered to a slip i just leased on Friday. Compression numbers were all between 160 and 170psi on a warm engine.

I appreciate the additional tips on what to try. I'm going to start with plugs, wires, and maybe distributor cap and rotor. I've never been good at reading plugs. Here are a couple of pics.

Maybe you guys can let me know what you think. I'll work on both of your suggestions this weekend.

Thanks for walking me through this.

MoonRiver · 07-25-2019, 05:52 AM

Those plugs are shot!!! New plugs, wires, cap, and rotor for sure and you might as well get a new coil while your there.

golfwins · 07-25-2019, 03:46 PM

Thanks for the confirmation. I thought so too, but wasn't sure. The tip looked odd to me, but I think it's related to the type of spark plug. It currently has NGK TR55GP installed and that model doesn't show up in the Mercury online parts catalog. I'm trying to decide on the AC 41-932 or NGK ITR4A15 right now.

Phillbo · 07-25-2019, 04:17 PM

What engine do you have?

golfwins · 07-25-2019, 04:20 PM

I have the 350 MAG MPI Serial # is 0M643181 which i think fits into the 0M600000 Thru 0W59999 Catalog # 90-884717. Thanks for your help.

golfwins · 07-25-2019, 04:22 PM

Here is the parts list I currently have put together. What is the general feel on Sierra parts?

Plugs:
AC 41-932
NGK ITR4A15

Plugs Wires:
863656A1

Cap and Rotor:
884792

Ignition Coil:
New#-863704T
Old#-8M0054588

mmwjr · 07-25-2019, 05:07 PM

Unfortunately my work computer won't let me see the pictures but it sounds like it's time for a complete tune up from what the others have said.

golfwins · 08-25-2019, 04:16 PM

Here are some codes I pulled this morning. I haven't started my research on them yet. Maybe it will give you guys some ideas. Maybe they aren't related.

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mmwjr · 08-25-2019, 06:06 PM

You only have a single engine, correct? There is no starboard or port engine, so my guess is the system is not program correctly for a single engine.

golfwins · 08-25-2019, 06:12 PM

The Vessel View program asked me how many engines I had. Are you saying the engine ECM/PCM isn't programmed correctly?

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