Boat will not plane

[Kenlee]

I am new to boating and need your guys help because I have no clue. I bought a 1977 Classic Interceptor 25 ft Cabin Cruiser. I took it out for the first time yesterday. No matter what I did with the trim the boat would not plane. It does have some dings in the propeller and the fin above the propeller is broken on one side. My rpm gauge doesnt work. The engine is hard to start but once started runs good. It says 260 on the valve cover and the guy I got it from says its a 350. It has a mercruiser alpha one stern drive. The fuel tank was full. I joined this group cause you guys know a lot about boats and Im dumber than a box of rocks when it comes to them. Where would you start to fix the problem? The only time the boat will plane is when its idling or barely moving. Any kind of throttle and the bow is really high and the stern looks like its gonna go under water. And there was about 2 or 3 gallons of water that drained out after i pulled the drain plug. Is that normal? Is that the water that was in the engine block maybe?

 

[SkiDad]

it sounds like it could be many things, but I would check these 2 things first

-- does your floor have soft spots ? If so you might have a lot of water stuck in the foam that is under your floor. I'm willing to bet you have wet foam if your bow is pointing that high. One quick way to check is to take your boat and trailer to the local truck stop and have it weighed on the CAT scales - this is around 10 bucks. I show you boat weighs around 5000 lbs - add 1500 for the trailer - so if you are way over 6500 lbs then you probably have some water.

-- Can check is to see if you all spark on all 8 cylinders.

if the above things are good then you might need to look at a lower pitch propeller.

 

[Kenlee]

I will take it and have it weighed. My floors are very solid though. Is it common for it to drain 2-3 gallons of water out after an hour? Thank you for your reply

 

[fhhuber]

2-3 gallons after an hr without splashing over the sides... you have a leak or the soaked foam is draining.

 

[Scott Danforth]

No, the water draining out is not normal. you have a leak somewhere. my guess is you have a lot of water in the hull too

post a pic of your dinged up prop and broken anti-cav plate

 

[kenk63]

check the bellows for a leak

 

[Kenlee]

No, the water draining out is not normal. you have a leak somewhere. my guess is you have a lot of water in the hull too

post a pic of your dinged up prop and broken anti-cav plate

I took a couple of pics with my phone and i cannot upload them because it exceeds the limit and i dont know how to make them smaller

 

[Kenlee]

2-3 gallons after an hr without splashing over the sides... you have a leak or the soaked foam is draining.

If my bellows were bad would that let water get to the foam? And if the foam is wet is there a fix? Or am i just screwed?

 

[Kenlee]

check the bellows for a leak[/QUOTE

Can you explain the easiest way to do this? Thank you.

 

[redneck joe]

bellows leak check then weigh.

 

[jimmbo]

First of all, are all the engine drains closed properly? Are all the hoses clamped tight? Was the boat dry(drained with nose high and drain plug out) before you first took it out?
the 260 on the engine refers to HP. Most 260s historically have been 5.7L(350), only the past 15 or so years have the 5L(305) made 260hp.
Are you trimming the drive all the way down before you accelerate?
BTW, boats don't plane at idle or low speed. Most don't plane until around 18 - 20 mph. the bow going up and the stern appearing to drop is part of getting on plane

 

[kenk63]

check the bellows for a leak[/QUOTE

Can you explain the easiest way to do this? Thank you.

with the out drive down, turn it to the left, then to the right, look in at the rubber bellows, put your had in there and see if you can find any cracks or tears, then do the same with the out drive up, if all is good, then check the clamps and make sure they are tight