Not enough engine?

[topjimmy]

I have a 2007 Lowe FS175 with a 90HP Merc Optimax. It is a deep V aluminum boat.

I have been skiing for years, but I cannot get up on a slalom behind this boat. I only weigh 115 lbs. I want to get a new prop, but the dealer says not until I have 20 hours on (I have 13 now).

When I swap props, will it make that much of a difference? Will I be able to ski behind this boat? I used to ski behind a 15 foot Alumacraft with a 55 Evinrude all the time. What gives?

 

[deejaycee_2000]

Re: Not enough engine?

Well I might have to agree that maybe you don't have enough engine ..... a new prop can give you better hole shot to pull you out faster but, a low pitch prop that have power doesn't have top end to give you the speed you want for slalom skiing .....

 

[Boatnik70]

Re: Not enough engine?

At your low weight, 90hp is more than enough to pop you up quickly on one ski. Find out what pitch prop. you have on there now, and drop down maybe two notches in pitch (i.e., if you have a 19-in. pitch, drop to 15, if at 17, drop to 13, etc.). Just make sure your tach. is working and don't overrev. your engine--you may well want to swap back and forth between your "skiing prop." and your "cruising prop.". Good luck!

 

[kenmyfam]

Re: Not enough engine?

I use a 14" X 17" pitch on my outfit for added hole shot and multi skiers and a 14" X 19" prop for general purpose. My outfit is described in my signature.

 

[OhWellcraft]

Re: Not enough engine?

While its true you don't have too much engine by any means a 90 should be plenty to get you up. A prop change can and will make a huge difference for you. As stated though you will lose mph off top speed to get a better hole shot. I would ask your dealer what all of the prop options are for that motor, There are usually 4 or 5 ways to go. I would stick with the alum. until you get it dialed in then maybe step up to a ss unit. As mentioned keep a good close eye on your tach. don't want to over rev a brand new motor. Also there are a few props out there that you can change the pitch on but I have never used one and most of the things I have heard have not been good. Try the prop section on this site and ask around see if others have experience with them...

 

[OldMercsRule]

Re: Not enough engine?

I have a 2007 Lowe FS175 with a 90HP Merc Optimax. It is a deep V aluminum boat.

I have been skiing for years, but I cannot get up on a slalom behind this boat. I only weigh 115 lbs. I want to get a new prop, but the dealer says not until I have 20 hours on (I have 13 now).

When I swap props, will it make that much of a difference? Will I be able to ski behind this boat? I used to ski behind a 15 foot Alumacraft with a 55 Evinrude all the time. What gives?

Wow those new Mercs don't have much hair do they?

I have a very old 1959 Scbrecraft 18 foot boat, (comparable to a modern 20 footer). Very high gunnels, sink, drawers, fairly light weight fer a fiberglass boat but much heaver then an aluminum boat.

It has a pristene 1969 Merc 1000 short shaft (100hp at the crank not prop like yer 90), with a three blade 17 pitch prop.

I weigh 210 lbs n' ski on an old Kidder Redline ski circa 1990 vintage, (very aggressive ski). I usually do a flyin' dock start because I'm an wimpy old fart n' don't like ta get wet but when I do deep water start it snorts me out like a cork. I could pull two of me NO PROBLEM, (done that), maybe three. Ya never want much slack on a dock start or you well dislocate yer sholders. What is wrong with yer motor?

No similar size n' weight boat n' same horsepower outboard motor, (Johnnyrude; Yammadinger; et al) will touch this old girl out of the hole till top speed, (no GPS but guess 40+ MPH based on the ol' speedo).

My $.02 JR

 

[mrfixitman40]

Re: Not enough engine?

well i am not a good skier but my old evinrude 75 hp on a deep v starcraft aluminum boat i got up just haven't figured out how to stay up yet my wife can stay up and gets out of the water easily so if i had to guess they cut back on your throttle for break in don't know if they do since i never had a new motor but i know my quad was limited until the break in time was up just an idea

 

[05GlastronSX]

Re: Not enough engine?

dont forget oldmerc that your 100 is an inline 6. Im pretty sure your old motor produces more torque than the 3 cylinder 90. Drop down in pitch and see if it helps at all. If not, you will either have to upgrade to atleast a 115 (preferably v-6 for all around performance) or be satisfied with what you have.

 

[OldMercsRule]

Re: Not enough engine?

dont forget oldmerc that your 100 is an inline 6.

Very True!

Im pretty sure your old motor produces more torque than the 3 cylinder 90.

Hmmmmmmm, might be. All I know is the older Mercs, (specifically: the larger inlines like I own), were and still are "screamin' demons" as another Merc ace said on a post I read here on iboats. Me two 1969 1000s only have 90 cubic inches n' they turn cornsiderable RPMs ta develope their power. Never thought of 'em as a torque heavy monsters like me ol' Ford FE blocks are. How many Cubic inches are the new 3 cylinders? Why would six little bitty jugs produce more torque then three big ones?

Drop down in pitch and see if it helps at all. If not, you will either have to upgrade to atleast a 115 (preferably v-6 for all around performance) or be satisfied with what you have.

I think the older Mercs were and still are underated. If the 100 cubic inch inline6 motors actually produced 155 HP at the crank as one of the screamin' 1976 1500s supposidly did, how could ratin' nearly the same motor at the prop generate a mere 115 HP in 1982? Seems ta me they jus' don't make 'em like they used to. But I only have one functional brain cell. Respectfully, JR

 

[Bigprairie1]

Re: Not enough engine?

Wow those new Mercs don't have much hair do they?

I have a very old 1959 Scbrecraft 18 foot boat, (comparable to a modern 20 footer). Very high gunnels, sink, drawers, fairly light weight fer a fiberglass boat but much heaver then an aluminum boat.

It has a pristene 1969 Merc 1000 short shaft (100hp at the crank not prop like yer 90), with a three blade 17 pitch prop.

I weigh 210 lbs n' ski on an old Kidder Redline ski circa 1990 vintage, (very aggressive ski). I usually do a flyin' dock start because I'm an wimpy old fart n' don't like ta get wet but when I do deep water start it snorts me out like a cork. I could pull two of me NO PROBLEM, (done that), maybe three. Ya never want much slack on a dock start or you well dislocate yer sholders. What is wrong with yer motor?

No similar size n' weight boat n' same horsepower outboard motor, (Johnnyrude; Yammadinger; et al) will touch this old girl out of the hole till top speed, (no GPS but guess 40+ MPH based on the ol' speedo).

My $.02 JR

...well I have to agree with OMR (at least this time)...what is wrong with that motor? Is it in good shape. That hp on that size of boat should quickly get you (115lbs?) up and out. Mercs are usually pretty good ski motors...maybe its time for a compression check to make sure your engine is in good condition.

 

[barts5oh]

Re: Not enough engine?

Let the engine break in a bit before playing with the prop, your dealer is right in this case. The motor should loosen up a bit by then. The 90 should still get you up unless your prop is really setup for top speed. Do you know the pitch? Do you have a tach? If so, what are the max RPMs that you're getting out of the engine. Until we know all the facts, the question can't be answered correctly. Does the motor "lug" or does it seem like it's slipping a bit?

As far as the early in-line Mercs are concerned, as is the V-4 OMCs of the
'70 & '80s, the displacements were the same but the "tuning" was different. When Mercury made the straight 6 engines, the 90 was the lowest HP rated, (and the most reliable) because it made it's power @4800 RPM, the 115 around 5200, the 140/150 @5500+. The exact numbers I don't quite remember because I gave up my outboard repair business years go. The differences in horsepower came from exhaust tuning and carb jetting. Resulting in power @ different RPMs.

 

[wire2]

Re: Not enough engine?

At one time I came out of the water on one behind a 15 foot Leavens with a 4 cyl 65 hp Merc. I was 190 lbs then.
I expect your motor will gain a bit of power after it's broken in.

Power isn't an issue with me any more, I have a 19 footer with a 300 hp I/O.

 

[Trevor9751]

Re: Not enough engine?

you have lots of engine there to pull you out I am over 200lbs and get out easily with 115hp are you maybe used to sking with a pole and now you are hooked lower on the transom I have seen that make alot of people think they are underpowered also pay attention to when your boat is planing out if it is one of those boats that has alot of trouble planing that will make it seem underpowered also just add a hydrofoil to fix that problem if all this is fine and you still cant get out with a 90hp then there is definatly something wrong with it as long as you are getting proper WOT rpm with the prop you have there is no reason you should have to reprop to pull a slalom skier

 

[OhWellcraft]

Re: Not enough engine?

I would guess that boat was not set up from the factory to pull slalom skiers, there is nothing wrong with changing props to find out what works best for you and your needs. Break it in properly keep an eye on your tach when using different props and you will be fine. Please don't use a hydofoil they are really bad for the lower unit and put a lot of un needed stress on the transom. If you have a planing problem use smart tabs they are a bit more money but well worth it. If all a motor needed to perform it's best was a piece of plastic stuck to the cav plate, they would come from the factory that way. I would also check your warrantee some are voided if you use hydrofoils.....

 

[jimmbo]

Re: Not enough engine?

People skied in the 50s and 60s when the average hp was less than 50hp and the biggest engines were less than 115 hp. In my teens and weighing 175 lbs I learned deep water starts on a salomn ski behind a 14ft runabout with a 40 Johnson . Mind you it could only pull me at 23mph. I had to wait till my dad bought a 16ft with a 90hp to ski over 30 mph

 

[ghind]

Re: Not enough engine?

Firstly, what is your WOT RPM? (How many RPMs is the engine doing at full speed, normal crew/fuel load).

A 90 is more than enough engine to pull a slalom.

The other trick is to learn to drag a leg. You start with your back foot out dragging behind you. It stops you pushing down on the back of the ski. Pushing like that just pushes a wall of water.

A high pole is not desirable to slalom on. It is just weird. Also, it give you more to lever against on the starts which lifts the front of the boat in the air. This just makes the boat drag and wastes horsepower.

Now, back to basics. What are your engine RPMs at WOT? What WOT RPM range is your engine rated for. What prop are you currently running? What pitch is it?

I'm sure you'll find that the right prop and learning to at least not drag your bum on the starts will make it more than OK.

I've pulled two blokes up before behind a 90 on a heavy 16 footer ....

 

[shipoffools]

Re: Not enough engine?

I run a 1988 70hp Merc on an 18' Starcraft aluminum bowrider and with a 17 pitch it has plenty of go to pull my 195lbs out slalom. I have some nephews,(and nieces boyfriends) that range from 200-250lbs and I have no problem pulling the experienced skiers amoung them on two skis.

I would let your motor break in a little bit more, then watch your rpm at wide open, you might be able to change pitch and find the holeshot power you need.

I learned to ski behind a 15' fiberglass runabout with a 40hp Evinrude, not the most exciting ride in the world but it worked.