7.5hp Gamefisher..........how fast?

[Capt Ron]

Re: 7.5hp Gamefisher..........how fast?

There's a fine line between the tabs producing a helpful lift or speed killing drag. Before ripping a tearing on them try to bend the bottom plate up and the rear edge down (collapse the triangle).

Well I can sit here all day or load up the rubber boat and go for a ride....Boat wins!!!

Capt Ron

 

[Warlord]

Re: 7.5hp Gamefisher..........how fast?

Well Capt Ron, I tried bending it and it just wasn't going to budge. The way they are mounted was very strong. So after staring at it forever, and with the die grinder in one hand and a crazy look in my eye.......off they came. Chop chop. I would rather start with some adjustable trim tabs and go from there. First though next week I am going to take the boat back out and see how it performs without anything. Then I will rig up some trim tabs and see if it helps. I will also try raising the motor when I am out and see if that does anything. At least with the GPS I keep an eye on the speed and see if it changes. Still any thoughts on if a Doel-Fin would help or would the trim tabs do more?

 

[Warlord]

Re: 7.5hp Gamefisher..........how fast?

So I took my boat out today, and experimented with the motor. First of all without the trim tabs or whatever they were, there was no change whatsoever. I also tried raising the motor 2 inches, but that only got me about another 1/2 a mile per hour. Then if I sat about 2/3 towards the front I picked up about another 1 mph. So I think my best speed was 6.2 mph, not much of an improvement. Of course the motor ran great all morning but later in the afternoon it started stalling out for no reason, then it got to the point where it wouldn't start. Being that it was over 100 degrees out on the lake I got tired of pull starting it, so I had to use the trolling motor to get back. Of course it got windy then the battery wore down and I was pretty much standing still and had to get towed back to the dock. Oh well since my 5 hp only goes a little slower and runs flawlessly, then 7.5 is going on craigslist. Oh yeah and guess what as soon as I towed the boat out of the water, it started and ran fine. THat motor has been trouble since I first bought it, so no more. At least I caught two fish when I was out.

 

[Capt Ron]

Re: 7.5hp Gamefisher..........how fast?

Sorry to hear this, makes you want to beat the tar out of it with a hammer doesn't it.
That's why they are known as frustration motors.

Is the throttle plate opening all the way?

I wonder if the carb on the 7.5 is not correct, as in transplanted from a motor of less hp.

Capt Ron

 

[Warlord]

Re: 7.5hp Gamefisher..........how fast?

Yeah tell me about it, but yep the throttle plate opens all the way. I am sure the carb is the right one since I have another 7.5 that I picked up for parts and everything between the two is identical. Just a pain in the butt motor. My 5 hp is also a Gamefisher but it runs soooooooooooo much better, but it is also 10 years newer than the 7.5. So I will just pass it on to someone else and start shopping for something in the 10-15 hp range. I know the Klamath Trailorboat 12 footers can handle 20 hp so I don't think I should have any problem putting a 15 max on mine.

 

[fishrdan]

Re: 7.5hp Gamefisher..........how fast?

Still any thoughts on if a Doel-Fin would help or would the trim tabs do more?

I have a StingRay on my 7.5 (came with it) and I removed it to see how it would work without... Let's just say that it's going back on the outboard ASAP My boat still planes, but it takes longer to plane and the bow rides higher.

That said, a hydrofoil isn't going to help your problem since the boat is underpowered. Don't know if this was mentioned, but you should have at least 70% of the hull's HP rating for good performance. A 15HP should do great.

 

[Warlord]

Re: 7.5hp Gamefisher..........how fast?

That said, a hydrofoil isn't going to help your problem since the boat is underpowered. Don't know if this was mentioned, but you should have at least 70% of the hull's HP rating for good performance. A 15HP should do great.

Well my boat is a 10 footer, but I know the 12 footers could handle up to 20hp. Based on the 70% formula, I should have at least a 10.5hp so a 15 could solve my problems..............I hope,lol.

 

[MSZ]

Re: 7.5hp Gamefisher..........how fast?

Owning an air cooled 1974 Sears 7.5HP engine for years, it probably only puts out 4.5-5HP and would get outrun by a 5HP normal water cooled motor.

I don't know how these were rated, but they are underpowered.

 

[Warlord]

Re: 7.5hp Gamefisher..........how fast?

Yep I am thinking the same, that the motors are very underpowered. It turns out the reason I had problems with it on the lake is that the fuel pump element ripped again. What I don't understand is that I put a new one in and it lasted for about a day. What would cause it to break. Either way this motor is up for sale very soon.

 

[fishrdan]

Re: 7.5hp Gamefisher..........how fast?

Carb cleaner will eat the livin *#%^ out of the fuel pump element, don't ask how I know

I didn't catch you had a 10'er, just the 20HP thing. Wonder what the HP rating is for your hull, or similar sized/designed boats?

 

[Warlord]

Re: 7.5hp Gamefisher..........how fast?

I know about how carb cleaner will kill the element, but I made sure not to use any since the rebuild. The carb was carb cleaner free, but one way or another the freakin element broke anyways. Hahahaha I will be happy to see the motor go away so I don't have to mess with it anymore. Of course I need to get it running so I can find a buyer. Now I just need to order yet another fuel pump element......................ughhhhhhhhhhhhh!!!