Bayliner contessa wont plane

[Justenough1986]

Hi all

i have a 1986 2850 contessa command bridge. Had it about 12 years andcso far managed to get it to plane about 5 times.

A llittle history. I got it cheap due to fact previou owner back it up on trailer caught leg damaging bottom of leg and snapping the yoke. There was no damage to shield. I got another yoke and brought a fully recon 280 leg ( apparently i dont think it was) after fitting and 1st run up river so about 6 knotts i checked oil and found it to be milky. Turned out to be the seal, not sure what its called but the square plate that the gear selector is, fixed that and oil was fine allthrough later had to change u-joints and top bearings..

i had taken itvon a quite a few slow trips but 1st time i opened it up, it blew a head gasket and made a mess out of engine. I replaced with a reconditioned engine from mercrusier. Std 260Hp

at wot about 4400-4600 she would do about 15/16 knots but make a big hole she sat in. I pulled engine put a comp cam extreme cam. Msd ign. New holley carb and although felt like she had more power. She still prefor same about 15/16 knots and a big hole.

tabs work when at dock but dont know if the work under load. I tried all sorts removed weight. Moved weight around . Replaced big heavy lead batteries with lifepo4 moved them under floor to reduce back eng weight, this done at different times over years. To no joy. about 5 times so far when she seams to get over that hump she make when she digs in. She has planed and done about 20/22 knotts. But very rarely

i thought she needed more power/torque so i built a chevy 400 engine. Bored 30 over full scat forged rotating assembl. Com cams roller cam that for 1200-5000 rpm range roller rockers 1.5 ratio. Afr 195 heads. Air gap intake and a sniper 2 efi fuel system with hyperspark ign.

shes running about 12.5 to 1 and 34 total advance. Pulls like a train but boats slower about 12 knots but a deeper hole. The leg on 2nd of the 4 holes closest to boat. I have tried 1st hole but not with new engine.

on last attempt she stuck in gear. Managed to get her out but bent a gear cable which snapped when trying to straighten it. Snapped. She will go in one gear fine but unless doing over 1500rpm jumps in and out of gear and doesnt change no matter how much i adj. cable

when i built engine i got a 16x17 prop and on last attempt she would do about 12 knotts ar 3200 rpm. So i swapped out for 16x13 i gad and she still do about 12knotts at 4400 rpm

now i can buy a fully recon 280 leg from a know good dealer and put new bigger trim tabs on her at about the cost of £5000 but will it fix issue and plane or am i just throwing away good money

shes had hull cleaned and antifouling not made any difference

sorry for long post but wanted to give as much info as possible

anyone have any ideas ?
thanks
andrew

 

[dingbat]

Sounds like you don’t have the proper prop on the boat.

What size prop are you running?

 

[Justenough1986]

Sounds like you don’t have the proper prop on the boat.

What size prop are you running?

Hi. As it says. I tried a 16x17 did about 12 knots @3200 then i put the prop that came with the boat. 16x13 which again did about 12knots @4400. The new engine feels more powerful but is slower but it digs a much bigger hole

 

[alldodge]

I would suggest taking boat and having it weighted

Boat spec says it's around 6K lb, so with gear and trailer its up around 10K. Wonder if hull is water logged

 

[Lou C]

Are you sure the outdrive is staying all the way down when you’re trying to get the boat to plane.

 

[Chris1956]

A 28 footer with a SBC is marginal on power, IMO. They ought to come with BBCs. Normally on those kinds of boats, with the correct prop, everyone must go into the cabin until we get on plane.

The correct prop is a must. Careful placement of load is a must. Try to load the bow as they are usually real stern heavy. Trim tabs can help a lot. If you can get a correct dry weight, on the hull and engine, you can weigh it and see if she has water somewhere.

 

[redneck joe]

you have a waterlogged boat. Live with chugging along at hull speed, pull motor and torch it or invest a year or better (with about $12k) to fix it.

 

[Justenough1986]

I would suggest taking boat and having it weighted

Boat spec says it's around 6K lb, so with gear and trailer its up around 10K. Wonder if hull is water logged

The boat was lifted couple a years ago by crane and it was just under 6.5k. At that time cant remember what fuel water etc i just remembering asking the driver as was curious

 

[Justenough1986]

Are you sure the outdrive is staying all the way down when you’re trying to get the boat to plane.

As far as i know yes

 

[Justenough1986]

A 28 footer with a SBC is marginal on power, IMO. They ought to come with BBCs. Normally on those kinds of boats, with the correct prop, everyone must go into the cabin until we get on plane.

The correct prop is a must. Careful placement of load is a must. Try to load the bow as they are usually real stern heavy. Trim tabs can help a lot. If you can get a correct dry weight, on the hull and engine, you can weigh it and see if she has water somewhere.

I have moved everything forward that i can. when sat still the top of leg is out of water. I would almost say shes bow heavy when sat still. I have looked in every crawl space etc either by looking or drilling a small hole and useing a camera on a stick kind of thing. All dusty execpt for a little bit in the bottem of the V

 

[DeepCMark58A]

Call me crazy but have you done a compression test on the cylinders?

 

[Justenough1986]

Call me crazy but have you done a compression test on the cylinders?

As i said its a recon engine bored 30 over with a brand new scat rotating assembly

 

[alldodge]

The boat was lifted couple a years ago by crane and it was just under 6.5k. At that time cant remember what fuel water etc i just remembering asking the driver as was curious

If the crane scale was accurate then the only thing left is you need more motor. The boat most often came with twin 225 of 260hp motors. Your setup sounds like the Formula 27PC I had with a single 454. The single motor didn't have enough power for the hull. I swapped out the motor a few times before having a 530HP 509 MPI and it would actually get up and go

 

[Justenough1986]

If the crane scale was accurate then the only thing left is you need more motor. The boat most often came with twin 225 of 260hp motors. Your setup sounds like the Formula 27PC I had with a single 454. The single motor didn't have enough power for the hull. I swapped out the motor a few times before having a 530HP 509 MPI and it would actually get up and go

He said it hadnt been calibrated but would be close. Was a few years ago but i been having this issue for about 12 years. I was hoping the new 407 would have been enough with its more hp and torque. It just makes and sits in a big hole . Once it gets over the hump it takes off. Alot more speed with a little rpm increase. I was hoping bigger tabs might help.

question… as the leg didnt come fromma great source. If it was a v6 ratio would it make that much of a difference?