boat speed seems too slow

[bigbelliedoldman]

I recently purchased two motors to put on my 11 ft vee bottom.the first I tried was a 1975 wards sea king 3.5hp that needed to be slightly choked to keep running.It struggled to make it to 4mph .I switched over to the 1985 evenrude 4hp and touched 6mph twice for a second or two but pretty much kept at 5mph.while using one,the other was near the front seat and not causing drag.The four hp was smooth as a kitten.the wards motor ia a two blade prop and the rude is a three blade. Am I expecting too much?

[frankr]

Probably

[Casey Lynn]

Just for grins lock your steering good and tight and move to the front seat for a few seconds. Watch what happens.

Anyway…..Hard for an 11′ boat to run above displacement speed with that hp.

[legendre]

quote bigbelliedoldman:

(…) a 1975 wards sea king 3.5hp that needed to be slightly choked to keep running

Plugged-up low speed circuit, or possibly bad crank seals? If it needs choke, that almost always indicates it’s getting too much air, somewhere..

[bigbelliedoldman]

pappy,I.m hoping that moving up in the boat was a joke,but then i could try it with an extention on the steering handle.The 3.5 hp sea king was acting like it was running out of fuel after about 30 seconds at full throttle,but slowing down wouldnt keep it running till slightly choked.if i ran just slightly choked it would do the same(want to stall)until i throttled down.i was thinking it was a fuel delivery problem.I’ll try some seafoam in the tank.it ran smooth in a barrel two months ago.

[tom-c]

I have a 10 ft Grumman V-bottom and always use a tiller extension. I put a board between the middle and rear seat so i can sit halfway between them and even a 3.5 hp will get me up on plane. If I use a 5 HP, the tank goes forward of the middle seat. I get about 16 mph on average.

[joshadurham]

I’ve done the move to the front of the boat trick. Just tighten the steering up and find a good straightaway. It got me up to 16 mph with my 56 Johnson 5.5hp. It’s pretty fun.

[legendre]

quote bigbelliedoldman:

pappy,I.m hoping that moving up in the boat was a joke.

No joke at all.. center-of-mass is quite important.

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