1990 Bayliner, 17', 3.0 won't get on plane...

[emilime75]

I know this gets asked a lot, and we've gone through a lot of things to try and remedy the issue without success.

The 3.0 didn't run when we picked this thing up. After some maintenance and repairs we got it running well and used it for the summer, that was 2 seasons ago. After the first season it was put away with a heater to keep it above freezing, but that failed and the head cracked. Purchased a rebuilt head, new head gasket, and a rebuilt carb to go along with it. All seemed well, boat fired up and idled well on muffs and in the lake. Slow cruising it does just fine, but the issue arises when we speed up and try to get on plane. It's slow to pop the bow up and it refuses to get on plane. The only way we can get it to plane is if a couple of us move to the very front of the boat and weigh down the bow, but it's still very slow. We've also gone out with minimal weight, me and a buddy, 1/4 tank of gas, nothing else and it acts the same.

So far we've done the following since purchase...

Removed water logged foam.
Replaced spark plugs and plug wires, it has electronic ignition so no cap and rotor to replace.
Rebuilt head, new head gasket, compression is good on all four cylinders.
Rebuilt carb.
Replaced fuel pump.
Added inline fuel filter.
Verified timing.
Replaced and verified correct pitch prop. I think it's a 20p, QuickSilver Laser II stainless, if i recall correctly.
RPM shows about right according to the tach in the dash, but we haven't verified if it is reading correctly.

What else should we be looking at? I read online posts how this motor in this size/weight boat should have no problem getting on plane. Any help or advice would be greatly appreciated.

Thanks

 

[alldodge]

Has it ever been able to get on plane?
If it has never been able to get up on plane then its either the prop or the drive ratio.

 

[thumpar]

What is the compression at? Have you done a leakdown test?

 

[emilime75]

Has it ever been able to get on plane?
If it has never been able to get up on plane then its either the prop or the drive ratio.

It did the first season we had it out. Not the second, which was last summer.

 

[emilime75]

What is the compression at? Have you done a leakdown test?

I don't recall the exact numbers, but all 4 were well within spec.

Have not done a leak down test, no.

 

[alldodge]

It did the first season we had it out. Not the second, which was last summer.

Replacing the head was needed, but something else has happened to the motor other then the head. Do a compression test again and I would thing it will be low.

 

[Rick Stephens]

Agree with AD. Potentially something wrong there.

I would also weigh your boat. If you are running a 20 inch prop, that boat would have to be really light. I couldn't swing that big of a prop with my 17 footer when it had a 3.0L in it. My boat would probably be a couple hundred heavier than your Bayliner.

 

[thumpar]

I was swinging a 19 with my 2.5l in a 16.5' so a 20 should be doable with normal load.

 

[fishrdan]

Is the timing advancing as it should, you'll need an advance timing light to check.
How is the fuel pressure, at idle and under load.
Did the boat previously run OK with the 20P SS prop, reach it's WOT RPM with a light load?
Was the replacement head the same design, and does it match the manifold? (there are 4-5 different GM 4cyl heads/manifolds)
Since the head cracked, did you check the manifold for cracks?

 

[mxcobra]

first thing you said was removed wet foam? well you may need to remove the wet everything else! also were did you get the heads? better check compression?

 

[Starcraft5834]

20p prop likely to much prop for your engine and boat weight.. drop down and consider a 4 blade prop.. will push you out of hole much easier