how much will a leak effect engine performance?

[85 Champ]

I couldnt decide which section to post this topic in. This is my first boat and i am learning a lot about it everyday, but im having problems. Its a 17 ft champion bass boat with a 1984 150 hp mercury black max motor. The problem Im having is the boat will not plane very easily. It requires the trim to be exactly perfect, and still takes some time to plane. The fastest was last weekend it planed in about 3-4 seconds the first time and by the end of the day it took about 10 seconds to plane. The motor seems to not want to rev very high for a couple seconds and then slowly starts building rpms and the engine eventually roars the boat onto plane. Once on plane it tops about 55 mph and runs very good.
Here are the items that I suspect. First, it had a leak in the hull, i spent last weekend chasing the leak and I think I have it fixed. Not sure yet, haven't tested it. I think that was a big source of the problem because when i have someone closer to the front of the boat it planes much easier. I believe the water is sitting in the back of the boat which makes the boat sit lower and weighted more heavily in the back.
Second, I dont know if its hitting all cylinders, checked the (brand new) plugs last night and 2 where wet. Going to do a compression and spark test tonight. Do wet plugs signify something is wrong? Dont know anything about carburetors, but have read on here that they may not be working properly, also have had friends recommend the accelerator pump, but not sure if this engine even has an accelerator pump?

 

[Chris1956]

Re: how much will a leak effect engine performance?

3-4 sec to plane is real good. Trim in all the way to start out. After planing, trim until the boat rides light and easy.

Wet plugs are OK, post the compression and spark test results. You need to figure out if there is water in the hull and get it out.

Your prop may be a bit too tall. What pitch do you have?

 

[85 Champ]

Re: how much will a leak effect engine performance?

Thanks Chris,

Plane - Yes the 3 -4 second plane was just fine by me, however it was only the first time and directly after i launched the boat. Each time after it took considerably longer....

Water - I think it's all out of the hull and any leaks are patched, I'll be testing this weekend at the lake. I really suspect this is the main problem for the slow plane. (I hope)

Trim - It never planes with the trim all the way down. I have to get it a little higher up to plane at all. About 1/4 up on the trim gauge. When the trim is all the way down, motor not only bogs down, but it starts sputtering like it wants to die. I believe that is due to water being in the hull causing the boat to sit lower in the water?????

Prop - im not sure what pitch, its a quicksilver Laser 2 stainless prop, it has 3 blades.

Will post the compression and spark results in the morning.

 

[j_martin]

Re: how much will a leak effect engine performance?

To answer your original question, when your trailer tires are squished to the rim, the foam in the boat is full of water. It won't drain or dry out, but it will make the boat a brick.

A 150 merc should push a 17' bass bote along in the mid 60's or faster.

 

[85 Champ]

Re: how much will a leak effect engine performance?

Thanks j_martin, although that wasn't what i wanted to hear, i think you are probably right. The boat sits about 3 inches below where it should while on the water, and although i didnt weigh the boat, checked tire pressure and is 41 psi, . I guess this is for a new thread.....

http://forums.iboats.com/showthread.php?p=2901731#post2901731

 

[Orbit Express]

Re: how much will a leak effect engine performance?

Word of advice. If you have your boat tied to a dock with a leak, and spend time in a resturant/bar/grill, it will probably sink. What would happen to a boat with a leak should your motor run out of gas, bust a prop, or kill a battery while on the water? Would you throw in the anchor? A 150hp or more will not help you. You have to ask yourself, WHY AM I LAUNCHING MY BOAT IN WATER WHEN I KNOW IT LEAKS?