When you say it won't plane out unless people are up front is the motor revving high and the boat not moving? OR is the motor struggling / laboring under load at a lower rpm until the boat planes out? Two very different problem paths.

What make of 21" prop?????

What he said!

I believe 1989 was one of the years you could have a 454 / alpha drive combo. If so, unfortunately they used the low hp 454 and called it a Magnum in this package. Why they called it a Magnum...why,oh why, we don't know.

That said, if you do have this package, the engine is 330hp and the outdrive has a low gear ratio of 1.32. That would mean you probably need a different prop for better planing.

I thought that was just 87 till the Bravo came out, but boat builders sold what they had til it was gone so possible. What RPM when doing 55?

No, it was for like 3 years. I posted the Merc documentation before, I'll try to find it again.

1986, 1987, 1988

Bravo was in 1988

celery stick came out in early 2000's - if I recall correctly 2004 year models. If he has an upgraded year model bravo then he would have it.

he says boat sat for years - I would run engine / boat on a remote fuel supply like I always mention. Do fuel samples from the boat gas tank. Check fuel pressure

Prob needs a full tune up. Cap, rotor, plugs, wires, plugs, ign coil and sensor under the rotor. But first I would a do a compression test and examine the spark plugs. Then move forward if that checks out good

possible boat / hull carrying extra weight - 1980's Baja very prone to wet rot. Is the floor and transom 100 % solid ? does you boat take on water ?