mad

[bodean98]

i have a 1994 startos 270 with a 1991 140 v4 evinrude. motor tached out at 4700 rpm with a 13x21 prop, so i tried a 19 and 17 pitch prop motor blowed out would not bring boat to plane. i put 12" jack plate and the same thing happened what can i check next

 

[bodean98]

Re: mad

i have a 1994 startos 270 with a 1991 140 v4 evinrude. motor tached out at 4700 rpm with a 13x21 prop, so i tried a 19 and 17 pitch prop motor blowed out would not bring boat to plane. i put 12" jack plate and the same thing happened what can i check next

when i say blows out the motor sounds like the prop is out of water and revs up

 

[Bob_VT]

Re: mad

Welcome aboard

You might have a multitude of issues here......

Have you verified the tachometer is correct?

Are you sure you are really running at wide open throttle?

Ventilation (aka blowing out) is from the wrong size prop. I would STOP buying props until everything is verified ....... retest you 21" and then post the results. Blow uot happens when the diameter is just a bit small.

If you can catch up with Dhadley and send him a PM (private message) ....... he is the most respected V-4 prop guy here

 

[bodean98]

Re: mad

no matter what i do i can not get no faster than 36 mph

 

[Bob_VT]

Re: mad

That does not sound right at all. You need to investigate the motor ....compression check and insure you are indeed firing on all 4 cylinders. It sounds like you are only running on 3 cylinders.

Is this a new to you boat/motor?

 

[steelespike]

Re: mad

Does the boat respond to up trim?Does the bow come up?
Or does the boat just lay down like its glued to the water.
Do you have a whaletale or hydrofoil on the motor?
What is the diameter of each of the props.
Is the anti vent plate(just above the prop)about even with the bottom of the transom.
36 isn't bad for 4700 but we need to figure out why 4700?
Does the throttle;e open all the way?
Get us the answers to these questions.

 

[bodean98]

Re: mad

this is a new boat and motor to me i bought it from a older man who didnt care about going fast, i do not have a whale tale or anything on it and another thing is the first time i took it out it ran hot so i put new water pump in it but it only produces about 8 pounds of pressure according to guage

 

[bodean98]

Re: mad

the boat does respond to trim but does not make difference to rpm or speed

 

[bodean98]

Re: mad

the butterflies are opening all the way, i have fire on all cyclinders the vent plate is even with bottom of transom but my transom steps back to bottom of hulli have a 13x21 prop on it, no whale tale, boat does respond to trim

 

[bodean98]

Re: mad

i put new water pump in and only getting about 8 pounds pressure according to gauge and only a dribble coming out of pee hole