Unable to Plain Out - Maxum Boat Owners Club

Trooper2928 · 09-24-2017, 09:08 PM

I have a 1997 Maxum 2800 SCR with a 7.4, 454 (carburetor) Mercruiser engine. The boat will get up to 3200 RPM's but will not plain out. I checked the bottom for barnacles and it is clean. I replaced the fuel/water filter, plugs, wires, distributor cap & rotor. Did a compression check and all is good. Had the carburetor rebuilt. After all of that the boat got up to 4200 RPM's and on plain a couple times but it was still struggling. Te following week, we were back to 3200 RPM's and not going up on plain. I pulled the fuel filter again and all fuel, no water in the filter. Thinking still could be water in the fuel or a bad fuel pump. Any Ideas????? Thanks.

biggerseagar · 09-24-2017, 10:30 PM

Got the right prop ?

Roger

Trooper2928 · 09-24-2017, 10:53 PM

Yes. Just bought the boat two months ago and was operating fine before we bought it. We also checked the props to make sure the bearings are good. Any further thoughts? Thanks for your reply.

mmwjr · 09-24-2017, 10:53 PM

Has the boat ever ran good for you? If so when was the last time and what has changed since then?

What drive do you have and what is the condition of the props?

biggerseagar · 09-24-2017, 11:02 PM

Is it the right pitch?

Roger

Trooper2928 · 09-24-2017, 11:16 PM

I am the third owner and the owner before me had the boat fro five years. The boat never planed out for me so I don't have much history on this boat. People on my pier say the previous owner didn't use it much. We first thought it was water in the fuel. The props are original (Dual) and they are stainless. They are in great condition.

Trooper2928 · 09-24-2017, 11:17 PM

Quote:

Originally Posted by mmwjr

Has the boat ever ran good for you? If so when was the last time and what has changed since then?

What drive do you have and what is the condition of the props?

I am the third owner and the owner before me had the boat fro five years. The boat never planed out for me so I don't have much history on this boat. People on my pier say the previous owner didn't use it much. We first thought it was water in the fuel. The props are original (Dual) and they are stainless. They are in great condition.

Trooper2928 · 09-24-2017, 11:24 PM

Quote:

Originally Posted by Trooper2928

I am the third owner and the owner before me had the boat fro five years. The boat never planed out for me so I don't have much history on this boat. People on my pier say the previous owner didn't use it much. We first thought it was water in the fuel. The props are original (Dual) and they are stainless. They are in great condition.

I believe it is a Bravo III outdrive

mmwjr · 09-25-2017, 12:37 AM

Since you are the third owned you cannot guarantee the props are origional nor the best pitch fir the boat. I would verify there pitch and compare it to what the quicksilver prop calculator recommends.

shrew · 09-25-2017, 02:30 PM

What is the Max RPM you're getting at Wide Open Throttle? Are you saying that it won't get up on plane at 3200 rpm? Or that the Max RPM you are reaching is 3200?

The engine should be at Max RPM at between 4400 - 4800 RPM. You should be able to reach those numbers.

One thing to look at is load and weight distribution. With a group of adults sitting in the cockpit, the boat will not get up on plane well. Where are coolers located? Other gear (e.g. Dinghy, dinghy motor, portable generator, etc)?

Phillbo · 09-25-2017, 04:05 PM

I have a buddy with the same boat. It was a pig and would struggle to get on plane and he would have to run it at close to max throttle to keep it on plane.

He bough ta set of 4 blade props from Hill Marine and it made a HUGE difference. Give them a call - Stainless Steel Boat Props & Accessories || Hill Marine

Trooper2928 · 09-25-2017, 04:38 PM

Quote:

Originally Posted by shrew

What is the Max RPM you're getting at Wide Open Throttle? Are you saying that it won't get up on plane at 3200 rpm? Or that the Max RPM you are reaching is 3200?

The engine should be at Max RPM at between 4400 - 4800 RPM. You should be able to reach those numbers.

One thing to look at is load and weight distribution. With a group of adults sitting in the cockpit, the boat will not get up on plane well. Where are coolers located? Other gear (e.g. Dinghy, dinghy motor, portable generator, etc)?

It will only get to 3200 RPM's and will not plane out. There was only four people on the boat and weight distribution will not effect how high the RPM's get. Surely, the boat was designed to haul more than four adult and two of us were at the operator position. Between of the two women seated at the stern only weigh about 225 together (one 105 and the other 120).

Lawnman · 09-26-2017, 11:56 AM

Did you check your throttle cable adjustment?

shrew · 09-27-2017, 02:22 PM

Quote:

Originally Posted by Trooper2928

There was only four people on the boat and weight distribution will not effect how high the RPM's get. Surely, the boat was designed to haul more than four adult and two of us were at the operator position.

Yes, it will. Ever try to redline a truck with a load going up a hill? How about peddling a bike up hill in the top gear. Are you peddling as fast as you possibly can?

Distribution of load will have impact when you're trying to get up on plane. Once up on plane, people can move where they want.

Perform the same experiment with everyone seated as far forward as possible, then see how different getting on plane is.