35 johnson weak?

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huntingtheworld

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Jun 13, 2010
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i went out with 4 people on my boat 14 foot tri hull and the motor bogged down.took 2 off and it ran fine.If i fill up the boat with fish its sluggish taking off.It goes 9 mph.with 2 people it goes 25-30.Should i get like a jackplate or something?The motor was on the first pin and the only one it will plain on.
 
Chinewalker

Chinewalker

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Re: 35 johnson weak?

What propeller are you running? Could simply be too much prop, not unlike trying to start off in 5th gear in your car...
 
bonz_d

bonz_d

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Re: 35 johnson weak?

1st thing I think you should do is look at the capacity plate on the boat. It will tell you the maximum hp that hull will support along with the maximum number of people or total weight.

I'm just guessing but I'd say it's underpowered and overloaded.
 
H

huntingtheworld

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Re: 35 johnson weak?

70 hp and 4 people.
ill get back with you on the prop.i have 2.I tried both of them.
 
bonz_d

bonz_d

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Re: 35 johnson weak?

Also look at the total weight. If that is say 1000# and you put four 200+ lb people, full tank of gas, batteries, anchors, paddles, life jackets, ect. you are overloaded. Then add that you are trying to push that with a 35hp engine then you are also underpowered.

Generally it is accepted the the boat should be powered to within 70% of it's max rating to get reasonable performence. You are at 50%.
 
milliesdad

milliesdad

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Re: 35 johnson weak?

start with basics-
Check compression and spark-using a real spark tester. should jump a 3/8ths gap with a white-blue snap.

when was the last time the carb has been cleaned?
 
H

huntingtheworld

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Re: 35 johnson weak?

milliesdad said:
start with basics-
Check compression and spark-using a real spark tester. should jump a 3/8ths gap with a white-blue snap.

when was the last time the carb has been cleaned?
Click to expand...

the motor is a 35 johnson and the boat is rated for a 70 hp.
the carbs were cleaned and new plugs 3 mounts ago.The boat runs perfect without 4 people.I weigh 135 and others 140+165+200+ marine battery 8 gallons of gas and 4 life jackets and a smaller anchor +100 in gear. was all i had.

my guess is 910 pounds.
 
bonz_d

bonz_d

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Re: 35 johnson weak?

hunting, I believe you that this engine is running fine and has no problems. Until you load it up. It just doesn't have enough power to push this at full capacity. A 14' fiberglass trihull with a capacity rated for a 70hp engine is not a light weight boat. Then add in the fact that there could be waterlogged foam under the deck and it's even heavier.

Going by the 70% rule that boat would need a minimum of 50hp to perform reasonably. Still don't know what the max weight capacity of this boat is but the best solution at this point would be to find a 13X9 pitch prop which is the smallest pitch prop I know of for the 35hp OMC.
 
H

huntingtheworld

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Re: 35 johnson weak?

bonz_d said:
hunting, I believe you that this engine is running fine and has no problems. Until you load it up. It just doesn't have enough power to push this at full capacity. A 14' fiberglass trihull with a capacity rated for a 70hp engine is not a light weight boat. Then add in the fact that there could be waterlogged foam under the deck and it's even heavier.

Going by the 70% rule that boat would need a minimum of 50hp to perform reasonably. Still don't know what the max weight capacity of this boat is but the best solution at this point would be to find a 13X9 pitch prop which is the smallest pitch prop I know of for the 35hp OMC.
Click to expand...

I'm sorry i got carried away with all the questions and forgot about that one.1100 is the weight including motor.
 
H

huntingtheworld

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Re: 35 johnson weak?

bonz_d said:
Now add in 120lbs for the engine and you are at 1030lbs which leaves a balance of just 70lbs.and you've reached it's max capacity with an underpowered engine.
Click to expand...

Well or maybe im a dumbass lol I just realised the motor is high as it will go but did fine with 2 people.Could the trim be the problem? the front was raised up a little.It is not electric trim.
 
8

82rude

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Re: 35 johnson weak?

trim is not likely the problem.that poor little 35 is just plain overwhelmed with 4 people.2 people she is maybe happy but then your chucking in an extra 350 lbs or so ,she not be happy.solution is less people or more motor to be quite frank about it.
 
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