Thoughts on upping my motor HP on my used Action Craft purchase

kevinopp

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Joined
Feb 7, 2012
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13
hi folks--

i'm just throwing this out since i'm pretty indecisive right now and am curious if anyone posts a response that may help me.

i used to have a 17' Action Craft with a 1997 130 Yamaha 2-stroke. the boat was rated to 150, but at the time the added weight of the larger motor would have offset and maybe worsened performance. i fish pretty skinny water, but with 2' 4", my trim tabs down and my 4 blade SS prop, i was able to explode out onto plane. it was really a hell of a boat, maxed out at about 45 MPH.

2 months ago i just picked up a 19' Action Craft 1890SE w/ a 150 Optimax on it, all from 1998. the original owner died shortly after purchasing the boat, and it was in storage for over 10 years. eventually someone decked it out with every accouterment one could ask for, and i bought it with literally only 102 hours on the boat and motor. it's all mint. i had a shop check the outboard before purchase, particulalry since there were issues with some of the larger Optimax's around the 1998 time. they said it's great, clean as a whistle, and all cylinder compressions were between 104-112. i've got a 3 blade SS prop on it right now, but it also came w/ a 4 blade as well. this is my first boat with a jackplate, so i'm still learning the best settings for the outboard trim/trimtabs/jackplate in shallow water. but all in all, i just feel the boat is underpowered. i'm barely hitting 38MPH w/ the 3 blade, and unless i trim the motor, plate and tabs ALL the way down, the boat points it's bow at the sky and cavitates like crazy before it catches. well, maybe it's not that terrible, but it certainly ain't close to my old boat.

so as far as i'm concerned, the boat really needs 200HP which is what it's rated for. and i really think it would make an enormous difference in its performance from every angle. everyone thinks i'm nuts for considering a new motor to replace what is practically a new motor in its own way. i would be happy with any Mercury/Yamaha/Evinrude DFI 2-strokes. i'm fantasizing that a dealer would take a trade-in on the old motor towards the purchase of a new one, but selling a 1998 Optimax, even with it's 102 hours just really isn't something that most shops want. of course i could try and sell it privately, but it's not like i can easily store a 500lb motor until someone decides it's the right thing for them.


i don't really know if i have a specific question.......i just know this boat is going to be with me for a long time, it's tricked out already to no end, and i am just dying to get a different outboard on there and have my perfect fishing machine. anyone have any musings on options that i have, what my motor might be worth, any trading websites that i don't know about, etc.?? the more i keep using this motor that i have and don't really want, the harder it will be to sell and the lower the price goes. several people have told me to run it until it dies an then get a new motor, but jeez.......who wants to fish and boat with a motor they don't care for and secretly hopes it's going to have problems?

btw, i'm on the east-central coast of Florida.


all 2? appreciated!!
 

The Rooster

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Apr 28, 2011
Messages
936
Re: Thoughts on upping my motor HP on my used Action Craft purchase

Welcome Kevin. Most of the concerns I've heard about were the larger 200-225 hp Optimax from around 99-2002. Those issues seem to have been addressed. 38 mph top speed seems a bit slow for that rig w/ 150 hp. Might need to do some more investigating on that one. Seems to me that time is on your side here. All depreciation has occured on that motor. Should easily be able to trade it in on new or slightly used motor. The larger 3.0 liter 200 hp block should be a nice upgrade in power over the smaller 2.5 liter 150-175 . Being in Central/South Florida, you're in outboard heaven. Should have plenty to choose from. Good luck !!!
 
Joined
Oct 22, 2007
Messages
2,598
Re: Thoughts on upping my motor HP on my used Action Craft purchase

How many rpm's are you seeing at full tilt boogie? With a light to average load you want to be able to get near the top end of the recommended rpm range for your engine. It's possible a prop change would help.
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: Thoughts on upping my motor HP on my used Action Craft purchase

It would seem the boat needs a setup adjustment,I sure wouldn't buy a motor at this point.
Give us the details on the prop.Tell us the wot rpm and speed by gps.
With the jackplate all the way down where is the antiventplate in relation to the bottom of the transom.
My info indicates the Actioncraft weighs about 1150 dry seems like a combo that could combine for speed.
Holeshot can be adversly affected by prop selection.
I looked up a bunch of tests with 150s and boats of your basic configuration most larger and heavier produced speeds from 45 - 50 mph.
 

kevinopp

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Joined
Feb 7, 2012
Messages
13
Re: Thoughts on upping my motor HP on my used Action Craft purchase

thanks for all of the input already!!

i have enclosed several pictures to help visualize what i have; adjusted for the best visual clarity. the 4-blade prop is a Trophy Plus, btw.

with 2 people on board and a light load (haven't stuffed all of the boat compartments yet), i was running about 5200rpm at 34ish, and pushing 5800+ at 38-39MPH via GPS. fwiw, most people thought my last boat would do 50+, but the fastest i ever went with the wind was about 46MPH. all of these numbers are from memory but should be accurate; i've actually only been on the water 2x thus far.

my mechanic thought the motor might be mounted too high on the transom based on the bow up/cavitation at full take-off that i described to him, but he was ok to go out on the water and see what was going on himself.

i never had the old Yamaha trimmed down as far as this Merc (as far as i can tell) to run full out, and if i wasn't dropping the trim tabs down a touch, the boat would begin porpoising. so obviously the tabs are taking from the high end and running up the RPM's as well. in this regard, the extra 2' on this boat are all in the bow (much longer nose), so the balance of the boat is very differrent than what i was used to.
 

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Joined
Oct 22, 2007
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2,598
Re: Thoughts on upping my motor HP on my used Action Craft purchase

Was the throttle wide open when you were running 5800 rpm? It's necessary to know that in order to determine if your prop pitch is where it needs to be.
 

kevinopp

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Feb 7, 2012
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Re: Thoughts on upping my motor HP on my used Action Craft purchase

Was the throttle wide open when you were running 5800 rpm? It's necessary to know that in order to determine if your prop pitch is where it needs to be.

i'm going to have to report back the next time i have it out. if anyone wants to give me a "list of things" i should do or look for, i'll be happy to comply.
 

Frank Acampora

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Jan 19, 2007
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12,004
Re: Thoughts on upping my motor HP on my used Action Craft purchase

I don't know About the bigger Mercs, But 104-112 psi seems awfully low for a 150 hp engine. Most I have seen are up around 145-155 psi. You might want to check specs with Merc technical help.
 

crb478

Lieutenant Junior Grade
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Dec 6, 2006
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1,036
Re: Thoughts on upping my motor HP on my used Action Craft purchase

As others have said we would need oto know how many rpms you are turning at wot. Looking at you pictures you may need to drop the motor down an inch or so, but its hard to tell from the angles. Is the jack plate all the way down in the pictures? Between the prop and the motor height there is probalby room for improvement.
 

kevinopp

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Feb 7, 2012
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Re: Thoughts on upping my motor HP on my used Action Craft purchase

I don't know About the bigger Mercs, But 104-112 psi seems awfully low for a 150 hp engine. Most I have seen are up around 145-155 psi. You might want to check specs with Merc technical help.

i'm not going to pretend that i have any idea, but this was a Mercury authorized service center that knew that i was possibly interested in buying a new motor if this one was bad, and they said the numbers were golden.
 

steelespike

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Apr 26, 2002
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Re: Thoughts on upping my motor HP on my used Action Craft purchase

I've looked and looked maybe I missed it but I don't see a prop size for either prop.
It would seem to me that the notch in the bottom could dirty up the water a bit.
Even allowing for the setback the motor appears a little high at about 2" above the bottom.
 

nwcove

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May 16, 2011
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6,293
Re: Thoughts on upping my motor HP on my used Action Craft purchase

hard to tell from the pic angles, but as mentioned, the motor looks like it could be lowered a couple (or three) inches. almost looks as tho the prop would be surfacing at plane.
 

kevinopp

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Joined
Feb 7, 2012
Messages
13
Re: Thoughts on upping my motor HP on my used Action Craft purchase

As others have said we would need oto know how many rpms you are turning at wot. Looking at you pictures you may need to drop the motor down an inch or so, but its hard to tell from the angles. Is the jack plate all the way down in the pictures? Between the prop and the motor height there is probalby room for improvement.

the jack plate is all the way down. and in all the shots, i lined up with whatever was the main focus in the shot, i.e. the antiventplate or the tunnel hull.

i'll have the boat out in the next few days and will report back with the requested numbers. for now, i'll go out with the 3 blade, although maybe i can change to the 4 during the outing to see whtat those numbers are.

it does seem like a lot of people, including my mechanic, think the motor is probably up too high.
 
Joined
Oct 22, 2007
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Re: Thoughts on upping my motor HP on my used Action Craft purchase

it does seem like a lot of people, including my mechanic, think the motor is probably up too high.

Don't be so quick to assume that. What's "conventional wisdom" for a V hull doesn't necessarily apply to a pad hull with a fair amount of setback like yours. I have my prop centerline 3" below the pad, which puts the AV plate WAY above the bottom of the hull. Looking at your photos it appears that your prop is lower than that, but it's hard to tell. It wouldn't hurt to find out what that measurement is on your boat so you have a starting point. With your trailer parked on a level surface raise or lower the front of your trailer 'til the bottom of the hull is perfectly level fore-aft. Then tilt your engine 'till the AV plate is perfectly level fore-aft. Measure the distance up to the bottom of the pad, then up to the prop centerline and take the difference.
 

kevinopp

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Feb 7, 2012
Messages
13
Re: Thoughts on upping my motor HP on my used Action Craft purchase

Don't be so quick to assume that. What's "conventional wisdom" for a V hull doesn't necessarily apply to a pad hull with a fair amount of setback like yours. I have my prop centerline 3" below the pad, which puts the AV plate WAY above the bottom of the hull. Looking at your photos it appears that your prop is lower than that, but it's hard to tell. It wouldn't hurt to find out what that measurement is on your boat so you have a starting point. With your trailer parked on a level surface raise or lower the front of your trailer 'til the bottom of the hull is perfectly level fore-aft. Then tilt your engine 'till the AV plate is perfectly level fore-aft. Measure the distance up to the bottom of the pad, then up to the prop centerline and take the difference.

Where do I measure for the prop centerline? And am I measuring from the ground up to the pad, or where the hull bottom is?
 

kevinopp

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Feb 7, 2012
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Re: Thoughts on upping my motor HP on my used Action Craft purchase

ok, i'm ressurecting this thread with some info that i got on the water yesterday. haven't had it out until then.

the distance in the above photo in red measures 22".

we had 3 people on the boat, and with a full throttle takeoff, i went right into the cavitation that i've described, bow in the air and not going anywhere. with a smooth increase in throttle, the motor and boat acted liked it should and went on plane. with the trim tabs out of the water, the jackplate down, and the motor trimmed down just enough to keep the boat from porpoising, we were doing 39.5mph at full throttle and 5800rpm's. if i took the throttle and literally pushed it up as far as it could go we hit 40.5 at 5900rpm's, but the throttle backs off by itself until it's at the 39/5800.

as i slowed down, the motor went into cavitation again; it roared, the rpm's went past 6000 into unknown territory, and the bow shot up. after about 5 seconds it "caught", the motor tone sounded normal again, the boat stabilized in the water, and the rpm's jumped down to 2700.

it's just a really bad sound and feeling with the cavitation. so thoughts are appreciated to try and fix this.
 

BonairII

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Jun 7, 2011
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Re: Thoughts on upping my motor HP on my used Action Craft purchase

If the prop is ventilating that badly, it seems like you need to figure a way to get the motor mounted lower.
 
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