10 mph top speed

johnfjohn

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Hi guys. New to the forum... but I have a 1976 glastron vegabond with a ford 302 Volvo outdrive... the boat runs amazing just rebuilt carb set timing dwell point gap. Engine its running too notch.. but once in the water it will not go above 2000 rpm. 10 mph... if I put the trim all the way up and the prop is half out of the water it will rev up and move a bit faster then 10 mph.... plz help im lost..... halfway New to boating..... ty all
 

KJM

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Hi guys. New to the forum... but I have a 1976 glastron vegabond with a ford 302 Volvo outdrive... the boat runs amazing just rebuilt carb set timing dwell point gap. Engine its running too notch.. but once in the water it will not go above 2000 rpm. 10 mph... if I put the trim all the way up and the prop is half out of the water it will rev up and move a bit faster then 10 mph.... plz help im lost..... halfway New to boating..... ty all
Don't run it half out of the water, you are sucking in air instead of water to the cooling system and ruining your impellor. She revs a bit more when half out because of less resistance on the prop, this don't really mean anything significant. "engine running too notch" what does that mean, or is a misspell? Will the engine run at higher rpms on a hose in the driveway (although reving her up too high for any length of time on a hose isn't recommended!)? Could your throttle cable need to be adjusted, Is there a lot of free play in the throttle before the engine starts to rev up?
 

johnfjohn

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Don't run it half out of the water, you are sucking in air instead of water to the cooling system and ruining your impellor. She revs a bit more when half out because of less resistance on the prop, this don't really mean anything significant. "engine running too notch" what does that mean, or is a misspell? Will the engine run at higher rpms on a hose in the driveway (although reving her up too high for any length of time on a hose isn't recommended!)? Could your throttle cable need to be adjusted, Is there a lot of free play in the throttle before the engine starts to rev up?
Ok sorry it was supposed to say top notch... the engine is dialed in.. and I have unhooked the boat throttle and opened the throttle by hand in drive and no change. And yes the engine revs fine on the muffs
 

KJM

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I;m no expert, what pitch is the prop? This might have an effect? Hopefully someone more knowledgable then myself might have some ideas.....
 

nola mike

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Ok sorry it was supposed to say top notch... the engine is dialed in..
Obviously not...
Is this a new to you boat? Have you checked compression? Double/triple/quadruple checked plug wire order? How old's the fuel? Have you checked/changed filters?
 

johnfjohn

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Aug 22, 2021
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Obviously not...
Is this a new to you boat? Have you checked compression? Double/triple/quadruple checked plug wire order? How old's the fuel? Have you checked/changed filters?
The engine is dialed in... New points new fuel new carb rebuild timing set dwell set... compression is the last thing I have to check
 

johnfjohn

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And yes new to me boat.....I was told its only issue was it sat for 2 years. I saw videos of it doing 30 35 mph... I'm lost
 

Scott Danforth

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Just under 1000
Way too high

RPM at idle is 650

What is your compression on all 8 cylinders?
What is your fuel pressure?
What did you set the dwell to?
Did you rebuild the carb from sitting? Did you clean the fuel tank If not, start there

Your motor is not running right. Its nowhere near "dialed in"
 

southkogs

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Is the prop hub spun? If it's revving out and you're not moving, that's a possibility too.
 

johnfjohn

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Way too high

RPM at idle is 650

What is your compression on all 8 cylinders?
What is your fuel pressure?
What did you set the dwell to?
Did you rebuild the carb from sitting? Did you clean the fuel tank If not, start there

Your motor is not running right. Its nowhere near "dialed in"
I promise you it is... I'm an ase certified tech. The fuel is off an auxiliary tank... I was gonna pull the main tank this winter.... I bumped up the idle a bit bc it would die under load at idle... I know the engine is not the issue here... I am not a master tech yet but I had 2 30 year master techs helping me with the carb rebuild(yes from sitting) and setting up timing. And dwell is set to 27 degrees... 30 degrees overall timing... all 8 have 120+ compression.... I don't know c what I'm missing???? Ty all for the help..... I am fine with v the engine side I don't know squat about the boat side
 

KJM

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Is the prop hub spun? If it's revving out and you're not moving, that's a possibility too.
He's not revving out, he can't get above 2000 rpm, so I figured that ruled out the spun prop (I had one myself one time). If the motor and gas supply are fine and the prop is ok, then it has to be the outdrive don't it? Maybe something jamming up acting like a brake?
 

KJM

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Wouldn't hurt to check the oil in the lower unit, even if its a long shot. Does the drive bearing sound loud? If I was sure the engine was not the problem, I would pull the drive and give that a good check over.
 

southkogs

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He's not revving out, he can't get above 2000 rpm, so I figured that ruled out the spun prop (I had one myself one time). If the motor and gas supply are fine and the prop is ok, then it has to be the outdrive don't it? Maybe something jamming up acting like a brake?
Yup. Good call ... missed that.
 

nola mike

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I promise you it is... I'm an ase certified tech.
I mean, congratulations on that. I can't tell you how many ASE certified mechanics show up on this board and can't diagnose the simplest problems. If your boat is revving at 2k and 10 mph, and you think all is well, more power to you. This is an engine problem, unless you have a hull carrying more water than engine. And 120 compression is a tired motor btw.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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I promise you it is... I'm an ase certified tech. The fuel is off an auxiliary tank... I was gonna pull the main tank this winter.... I bumped up the idle a bit bc it would die under load at idle... I know the engine is not the issue here... I am not a master tech yet but I had 2 30 year master techs helping me with the carb rebuild(yes from sitting) and setting up timing. And dwell is set to 27 degrees... 30 degrees overall timing... all 8 have 120+ compression.... I don't know c what I'm missing???? Ty all for the help..... I am fine with v the engine side I don't know squat about the boat side
its not a boat side thing

you can promise all you want, your not within spec, maybe you missed 4-cycle 101?

your compression is low (should be 140-150 psi) it will run, however you are down on power by 30% or more

you have an engine issue, primarily a lack of fuel flow and not enough squish to go bang

have you check to see if the flappers are still where they belong or did they get burned from an overheat and drop down and plug the exhaust?

dwell spec is 28-32 I try to shoot for 32 as the points wear, the dwell drops (back to points 101 that they taught in high school)

your timing is also off just a bit. should be 8 degrees BTDC and 24 degree advance curve so all in at 32 degrees

reset your dwell and timing to spec as well as the idle (650 RPM in gear)

again, what is your fuel pressure? should be about 4-6psi. if not, you have a fuel delivery issue. could be a restriction before the fuel pump such as a clogged filter (since you state you are running from a remote tank)

you may have to go back to the carb, make sure each passage is clean by passing a fine wire thru every passage.

what primary jets do you have?
what power valve do you have?
float setting?
 
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