Hi! New to the forum, first time posting here. Well, this is my first boat. I live in Central Missouri, so naturally I am striving to get a flat bottom Jet drive...but until I save that Money, I just picked up a 1970 14' V bottom jon boat with a 1975 Evinrude 25hp prop. I know it is a V bottom, but only the first third is the V, then it flattens out like a flat bottom...suppose they are all that way.
SO, the problem seems to be a fuel issue or an aerodynamics issue, I know aero has to do with air, but you catch my drift lol The boat with just me in it, gets up on plane, engine is humming at top RPM and we are cooking up the rivers pretty good. Everything seems as it should be. The guy who sold me the boat SAID that a 25HP on this short v bottom, pushes it pretty good. And I would say it is pretty quick.
NOW, add my father in the boat with me...and the boat most of the time seems as though it is only at 60-75% throttle...I have the tiller twisted as far as it will go, but the boat just won't get up on plane or get up in the RPM's. It seems as though something is holding the motor back, and the extra weight is just enough to keep it from cracking loose and getting up on plane.
What I have done so far is checked the fuel pump, seems to be pumping enough fuel, tho I have no baseline to know for sure. The timing is in order, and the points look pretty good. The carburetor I was TOLD was freshly rebuilt, and it does seem to be since the gasket on the bowl seems new. New spark plugs. And I have a tank of fresh 89 octane, so no old gas. When we got the motor, it wasn't running properly. After adjusting the points, new plugs, replacing a sheered off Keyway on the flywheel, and fixing the choke...it starts almost every time on the first pull now. Also, when the motor was mounted on the boat when we got it.. the anti cavitation plate was hanging about 2" from the bottom of the transom, and 5/8" or so below the keel, or V channel thing that runs down the middle of the boat. From what I had read, that was too low...so I added a 1" square piece of steel and raised the motor up about one inch. So now the plate is even with the keel, and about 1" below the transom. after running it today, It still seems as though even with the adjustment in height, the water seems to be riding at least an inch over the top of the cavitation plate...is it still too low on the boat? Are the fluid dynamics of the hull what is holding it back? I know it is riveted, should I try to smooth the hull out some, raise the engine more? Is there not enough fuel? LOL these are the questions pinging around in my head....it seems with just two adults of average size, this engine should be pushing alot better. I'm not sure how much I trust this guy....so maybe the carb does need some work. It just seems as though the engine is being bogged down.
Any help is appreciated
SO, the problem seems to be a fuel issue or an aerodynamics issue, I know aero has to do with air, but you catch my drift lol The boat with just me in it, gets up on plane, engine is humming at top RPM and we are cooking up the rivers pretty good. Everything seems as it should be. The guy who sold me the boat SAID that a 25HP on this short v bottom, pushes it pretty good. And I would say it is pretty quick.
NOW, add my father in the boat with me...and the boat most of the time seems as though it is only at 60-75% throttle...I have the tiller twisted as far as it will go, but the boat just won't get up on plane or get up in the RPM's. It seems as though something is holding the motor back, and the extra weight is just enough to keep it from cracking loose and getting up on plane.
What I have done so far is checked the fuel pump, seems to be pumping enough fuel, tho I have no baseline to know for sure. The timing is in order, and the points look pretty good. The carburetor I was TOLD was freshly rebuilt, and it does seem to be since the gasket on the bowl seems new. New spark plugs. And I have a tank of fresh 89 octane, so no old gas. When we got the motor, it wasn't running properly. After adjusting the points, new plugs, replacing a sheered off Keyway on the flywheel, and fixing the choke...it starts almost every time on the first pull now. Also, when the motor was mounted on the boat when we got it.. the anti cavitation plate was hanging about 2" from the bottom of the transom, and 5/8" or so below the keel, or V channel thing that runs down the middle of the boat. From what I had read, that was too low...so I added a 1" square piece of steel and raised the motor up about one inch. So now the plate is even with the keel, and about 1" below the transom. after running it today, It still seems as though even with the adjustment in height, the water seems to be riding at least an inch over the top of the cavitation plate...is it still too low on the boat? Are the fluid dynamics of the hull what is holding it back? I know it is riveted, should I try to smooth the hull out some, raise the engine more? Is there not enough fuel? LOL these are the questions pinging around in my head....it seems with just two adults of average size, this engine should be pushing alot better. I'm not sure how much I trust this guy....so maybe the carb does need some work. It just seems as though the engine is being bogged down.
Any help is appreciated