Boat won't plane out and bogs engine down

[Bodine74]

Hello,
I have been have problems getting my boat to plane out. I have a 14' deep v mirrocraft with a 20hp 202hg model Chrysler motor. At first I thought it was the motor so I rebuilt the fuel pump. New fuel filter, new fuel hose. Took it out last night and it planed one time and ran great at a good speed. All other attempts and it would not plane out and motor just bogged down. Could it be the motor? Or maybe prop? I'm at a loss on what I can do. Any help or ideas would be greatly appreciated.

 

[southkogs]

Welcome aboard Bodine:

What is the max HP your boat is rated for? Did it plane out in the past, or is this a "new-to-you" boat?

 

[Bodine74]

Max hp the boat is rated for is a 35 hp. This boat is my first. It did plane out and still sometimes does. When I first purchased it ran great. This problem does not happen all the time just most of the time. I thought it was a fuel problem because when it first started I could pump the primer bulb and it would run great. I'm just not sure what to look at next. The motor was completely rebuilt including the carb when I got it.

 

[Bodine74]

I will add that I am mechanically incline and used to work on cars/trucks for a living. So I like to fix things myself but I'm at a loss after trying everything I know.

 

[southkogs]

My first thought is that the boat is under powered. As a rule, you want at least 75% of MAX HP to run well ... in your case 75% would be about 26HP.

When the boat does plane out is it when you've got a lighter load on board?

 

[Bodine74]

I've had myself the wife and 3 kids on it and it planed out no problem.

 

[Bondo]

Ayuh,.... Welcome Aboard,.... Probably oughta do a compression test to be Sure of the motor,....

If it comes out all right, I'd go back to the carb,....
A rebuild is only good, til the next time crud, 'n water are pumped through it,....

 

[Frank Acampora]

As mentioned above, FIRST do a compression test on the engine. 120 PSI would be considered very good, (probably above factory specs.) and 90, in fact 80 would be acceptable. Then pull the flywheel and check the points. If the engine is an auto-electric with starter motor and light on top this is a little complicated to do. Go over to the Force/Chrysler forum with compression results and we can give you more detailed help.

As always recommended, put a cheap plastic inline fuel filter BETWEEN the fuel pump and carb. Check the fuel system from tank to carb. Pay special attention to the tank pick-up screen (if equipped) and the quick-connect fuel fittimgs for partial clogging.

 

[64osby]

Is is possible you have overloaded the boat or the weight was all in the stern.

 

[Mrcleaningguys]

Don't forget to run your bilge if you've got one. My 16 ft fishing boat has a 50hp mercury on it. During the walleye run, sometimes I would get upstream easily and sometimes it would seem like I was using a trolling motor. Apparently I was taking on more water than I thought and had to run the bilge anytime I stopped or slowed down.

 

[fishin98]

. Sounds like fuel issue...a piece of junk got into one of Carb orfices, check the Carb bowl for junk. As mentioned before, fuel pickup in tank....might have junk in the tank or clogged screen. Another thing to check.....is your motor running cool....peeing out a good constant stream of water...a motor that is overheating will degrade performance to the point of seizure.

 

[Bodine74]

Ok I check the compression today. Both cylinders are at about 130 psi. So that is good. I replaced the plugs and took it out. It bogged at wot until I primed the bulb constantly. When doing that it ran fine. I drifted and fished and came in with less than half a 6 gallon plastic tank and it ran great no problems at all. I don't get it. I always keep the fuel tank full usually. Maybe the gas tank. I'm wondering if having it less than half full tank had something to do with it. Maybe try a different fuel tank? I just don't get it cause it's so random.

 

[fishin98]

Ok I check the compression today. Both cylinders are at about 130 psi. So that is good. I replaced the plugs and took it out. It bogged at wot until I primed the bulb constantly. When doing that it ran fine. I drifted and fished and came in with less than half a 6 gallon plastic tank and it ran great no problems at all. I don't get it. I always keep the fuel tank full usually. Maybe the gas tank. I'm wondering if having it less than half full tank had something to do with it. Maybe try a different fuel tank? I just don't get it cause it's so random.

This may be trivial.....did you open the on vent the fuel tank?...I know, I know...just like asking the question.... did you put the plug in as the boat is sinking.
A unvented fuel tank will create a suction that will not allow fuel to properly flow to the motor.

 

[coolbri70]

check the fuel pump again, if it runs good while pumping the bulb, probably fuel issue, you rebuilt the pump i would doublecheck that may be a leak in the line feeding the pump too