Outback.. kinda slow.

[usaski1]

So I have an outback, and did a WOT test yesterday, with nearly empty fuel tank, and 4 people, stock OJ 13x13 prop. 3 blade. Wot was 38 mph on the speedo (forgot to check PP) and 5050 on the rpm's. Shouldn't I be getting to about 5200/5300 on rpm? Also thought top end should be about 44 mph.

[bzubke1]

Did you GPS check it? Could be your speedo is a little off. Also when I went from the stock 13.7x17x5 prop to a 14.25x14.5 on my mobius I gained a little on the top end because with the stock prop at WOT i could only get to 4500 rpm max. With the wakeboard prop it would actually get to max rpm at WOT.

[deerfield]

usa - Your max boat speed should be in the 40s. If memory serves me correct, last season my '07 Outback at WOT hit 45 mph, running w/ factory propeller. - Deerfield

[DOCDRS]

So I have an outback, and did a WOT test yesterday, with nearly empty fuel tank, and 4 people, stock OJ 13x13 prop. 3 blade. Wot was 38 mph on the speedo (forgot to check PP) and 5050 on the rpm's. Shouldn't I be getting to about 5200/5300 on rpm? Also thought top end should be about 44 mph.

All depends which motor you have. My 99 0utback would do 44 at 4500 rpms with the stock prop. Did both speedo's register same speed , and as above , I'd check it against gps. What did you used to get speed and rpm wise?

[Mikey]

I agree with Deerfield, stock prop and WOT should be just under 5000 rpm and around 44,45 mph.

[jmvotto]

usa - Your max boat speed should be in the 40s. If memory serves me correct, last season my '07 Outback at WOT hit 45 mph, running w/ factory propeller. - Deerfield
X2 our 07 obv would do 45 to 47 wot on glass just me same stock prop.

[usaski1]

going to have to do some more tests with the stargazer gps. I think with it off, it will tell you the speed.

[maxpower220]

Owners manual for your boat states 4400-4800 WOT range if you have the 325 hp motor.

[usaski1]

Strange, if 4800 is max WOT, why would the rev limiter be set higher? I know I saw 5050 on the digital tach (perfect pass)

[smokedog2]

Found my Perfect pass to be a little tight and WOT was not really WOT. Although, your RPMs sound about right.

SD2

[rdlangston13]

ive run my 08 LSV with the 325 up to 5200 rpms, but with the stock wakeboard prop i was only pushing right at 40 mph. i ran the stock axis prop for a couple days and it is a 13.7x 16 or so and i had about the same top speed but the motor would not turn much over 4900 rpm. my new 1847 topped out at 37 mph at 5000 rpm with my girl and i in the boat

[jmb]

My PP GPS seems to stop at 42MPH while my speedo goes up to about 46 MPH. Whats up with that????

[usaski1]

Whats up with that is that your speedo is off. If PP gps says 42, your going 42, not 46 as indicated.

Tonight I was running 3700 rpm for 30mph.. as noted by PP GPS. Something is strange.

why would I have to turn that many rpms for 30mph?

[zabooda]

I assume you all are on a lake as anything else and the gps won't show the true speed on the water.

[usaski1]

I've heard of this gps over water / gps over land stuff, but whats the difference? AWSA defines it as speed across the bottom. (whatever that means) if the gps is reading 30mph in the boat, it should read 30 driving down the road with the system off, on the trailer, right?

[jmb]

Whats up with that is that your speedo is off. If PP gps says 42, your going 42, not 46 as indicated.

Tonight I was running 3700 rpm for 30mph.. as noted by PP GPS. Something is strange.

why would I have to turn that many rpms for 30mph?

Yes, but I have some throttle left and am still speeding up when PP tops out

[jmb]

Whats up with that is that your speedo is off. If PP gps says 42, your going 42, not 46 as indicated.

Tonight I was running 3700 rpm for 30mph.. as noted by PP GPS. Something is strange.

why would I have to turn that many rpms for 30mph?

The speedo reads correctly and in line with perfect pass at speeds lower than 42MPH and is in line with the RPM's

[KSmith]

I've heard of this gps over water / gps over land stuff, but whats the difference? AWSA defines it as speed across the bottom. (whatever that means) if the gps is reading 30mph in the boat, it should read 30 driving down the road with the system off, on the trailer, right?

I think he is referring to static bodies of water versus moving bodies of water such as rivers as the speed of the current plays into the speed and if one is going up or down stream.

[KSmith]

Tonight I was running 3700 rpm for 30mph.. as noted by PP GPS. Something is strange.

why would I have to turn that many rpms for 30mph?

Are these speed and RPM issues new? If not what speed were you able to reach at what RPM previously?

Turning 3700 RPM to hit 30 to me would be sign that the prop pitch is too small. A 13 x 13 prop is pretty small IMHO. 13 pitch should have killer hole shot but you lose top end as compared to say a 13x16 or 13x17 would have less hole shot but longer legs at the top end. Many of the wakeboard props being run are in the 14 point something x 14 point something ranges. 14 point something pitch is great for hole shot and slow speed pulling for boat weighted down. If you are after higher speeds for skiing then I'd probably look at a higher pitched prop. But then again, your max RPM concerns me. Unless you are hitting the limiter at 5000 if the prop had too low of pitch then the engine should be able to spin up higher into the danger zone. If you are maxing out at 5000 and not hitting the limiter then it would seem that you are already running as high a pitch as the engine is capable of turning at WOT.

[zabooda]

X2 on both of KSmith's messages. An Outback unloaded (no ballast) should have a top speed in the 42-45 mph range with the rpms around 4800-5000 using the 13x13 prop. That prop is what I use and when my speedos go out I can correlate my speed to the tach and it isn't quite a 1:1 match. Something is restricting your power output.

[usaski1]

I don't know. I'm suspecting a fouled plug or issue with the ignition system (spark) it runs smooth, but feels weak. Like I pull a 150lb guy up (slalom) and it takes 80% throttle. and now I'm only running 38mph on top end? And 3700 on the tach for 30mph is just way strange. Don't know what to make of all this.

[usaski1]

trided it again.. 5020 on the rpms at WOT, gps checked 38.7-9 never hit 39mph. I just don't understand it. I think it used to go faster, but I'm not for positive. Maybe I need new spark plugs or something. 2 people in the boat, some boards and skis and 1/4 tak of gas. Strange.

[DOCDRS]

def change the plugs, my outback would lose about 2-300 rpm with a fouled plug. that does seem slow. I would think you should get 43 at least, what motor do you have?

[usaski1]

Yeah, its been feeling kinda weak. Might also explain the seemingly increased gas consumption. I have the 325. EFI Indmar. Got 85 hours on her.

[usaski1]

Also boat died 2x today at idle. Idle is correct at about 650 rpm's.

[brad460]

Rpm and prop will determine the speed. So...regardless if you are running on one or eight cylinders rpm is rpm...and that rpm will determine the speed. Now, if you have an acceleration problem I would be concerned about the engine or if rpm was low I would be concerned.

In my opinion, I think you are confusing the issues. Lack of acceleration and high fuel consumption are one problem. The top speed is not a problem but a result of the rpm and prop.

Stop focussing on the top speed and concentrate on the lack of acceleration and high fuel consumption. Start with the ignition system...

[usaski1]

Good idea, can someone provide me the part number for ac delco spark plug for the 325 efi indmar? I looked it up last night and didn't write it down. Also, basic mechanics, whats the best way to check for spark? Yes, I can pull the wireds 1 bo 1 and then hold near engine case and check for sparks, but any other way? that'd take 20 min and 8 starts on a v8.

[usaski1]

Good ol Moomba Boards, the info was already online for the spark plugs. I need to add to my tagline to "search before you post" I'll report back in a day or two weather it worked.

[usaski1]

Dang, no improvement.

Changed all 8 plugs, one looked oily. 5050 on the tach = 38mph. At all speeds, tach read 500-700 higher than It should. at 30mph, I was doing 3700 on the tach. What is up with that? 13x13 stock OJ prop. plug change wasent a waste though, it was time per maintenance anyway, and hopefully it will solve my stalling issues.

[sled - 1]

All seems very strange to me. MY 07 outback runs a solid 44 mph, I rum a 13x13 4 blade stainless, not very smooth but my approadch to my lift is very shallow and I churn up a lot of sand so its a no brainer...go stainless.

I have around 240hrs on my boat and have never changed a plug, in fact other than oil changes once a year and fresh water impeller I've never done a thing. Correction, I was eating coolant hoses a few years back, but an inline filter corrected that problem.

Oily plug, lack of power, stalling out. go through a few more things
1. fuel filter
2. compression test
3. coolant flow (is there something in the system causing it to run a bit warm
4. check rpm's on a hand held tester
5. use hand held GPS's to verify speeds
6. Strut and strut bushing
7. engine alignment

Something is stealing power, find it and fix it :)

[viking]

I agree with Sled. I Run the OEM blade and very rarely will I push over 4800rpms and will be around 44mph at that.

[usaski1]

So there are a ton of things Sled told me to check for, but I'm kinda thinking, I'm getting 5k out of the motor so regardless of any compression issues, or fuel filter issues, that 5k should translate to more then 38mph. I talked to my neighbor, and he thought it might be the prop... but if it were the prop, id be saying I'm at WOT and only getting 4500 rpm?!! It just feels like if it were a motor issue, I wouldn't be getting the rpm's in the first place. If something was binding (shaft?) I'd be getting low rpms... Its like something is slipping. Im turning 5K, but my prop isn't. Starting to get frustrated.. and it dies again tonight at idle (in nutral) I'm thinking fuel filter now. How many rpm's are you turning at 44mph?

[rdlangston13]

Did you post your prop diameter and pitch?


Sent from my iPhone newtys droid killer using Tapatalk

[usaski1]

Yes, standard 13x13 OJ 3 blade.

[zabooda]

At 5K rpm, it appears that you have something slipping and not giving you full torque as 4800 rpm and 44 mph seems about right. It would be interesting to see the rpms at the shaft as the tranny is a 1:1 so engine output shaft speed should equal the prop shaft speed. I'm not a mechanical kinda guy but is there something with the tranny that could cause slipping?

[DOCDRS]

I am assuming that you have checked the tranny fluid and it has been changed appropriately. Look closely at your prop and verify the diam and size. If they check out then I would tend to agree with Zabooda. Or you are under propped.

[usaski1]

Thanks for all your help guys... This is really frustrating. Im going to check the tranny fluid tonight. Is ther any other shade tree mechanic way of checking to see if I'm slipping? Also, If I have been slipping, have I been killing my tranny? Also If UI was underproped, I'd be "rippin it" (mass acceleration) out of the hole. Im not. In fact, acceleration is one of me current beefs with the boat. Dispite 325hp. that should be more than enough to get 'er done.

[usaski1]

Tranny Fluid okay. :-( checking and cleaning flame arrestor now.

[Mikey]

As someone mentioned previously,maybe you want to try an external tach to verify that the indash tach is actually working properly. I run a 13x12 3blade stock prop and usually run 4800 ish rpm and 43,44 mph. Maybe you are being misled somewhere?.. As for tranny check level is correct as overful can be as bad as underfull.??

[kaneboats]

May want to check and make sure you're not carrying a bunch of water somewhere in your hull. Is your bilge pump working right?

[usaski1]

Water in hull.. no. flame arrestor, cleaned.. was dirty, didnt help. put a mark in prop and shaft, pulled 3 sets. will test again.. not sure. 30mph 3700 still on the tach. If i had bad compression in the motor, I wouldnlt turn 5k on the tach, right? Thinking its not the motor. Its either the shaft, tranny, or prop, or some combonation, interactin between the 3.

[viking]

alignment?

[rdlangston13]

i dont think alignment would take away speed, just cause a vibration.

im no expert on these velvet drive transmissions but i would assume they operate more like a standard transmission just without a clutch. there is no torque converter and nothing to slip since i believe there are actual shaft driven gears that just use synchros to mesh up and smooth out shifts in and out of gear. to me this has to be prop issue if the motor is indeed turning 5000 rpm.

[KSmith]

Sounds like it's time to haul her into the shop and have her checked out.

[usaski1]

Not quite yet.. I'm going to put a differn't prop on it and see...

[bzubke1]

Is the motor still dying at idle sometimes? I would get the motor running right then go from there.

[usaski1]

***************SOLVED**********************

Put new 13x12 ACME prop on it.. runs 46mph depending on wind / chop, ect. better holeshot.. like a new boat! Im SOOO HAPPYY!!!

[KSmith]

What are the RPMs now at WOT?

[usaski1]

WOT is 4800. and 46mph by gps on glass with no wind. with wind chop? 42 or so...
feels like a new boat.. still got a little vibration, but that is while turning all the way left at 800 rpm or so (picking up skier, ect) Also, next issue is I have a fair ammount of play in the wheel before the boat turns now.. like a hands width or so... what needs tightening?

[KSmith]

Strangest thing I've ever heard... you were running 38 MPH, 5050 RPM with a 13 x 13 prop.

You put on a smaller pitch 13 x 12 prop and lost 250 RPM to 4800 but gained 8 MPH to 46?

In my experience that is exactly the opposite of the physics in my world.

[maxpower220]

Strangest thing I've ever heard... you were running 38 MPH, 5050 RPM with a 13 x 13 prop.

You put on a smaller pitch 13 x 12 prop and lost 250 RPM to 4800 but gained 8 MPH to 46?

In my experience that is exactly the opposite of the physics in my world.

Who knows what kind of damage that the 13x13 prop had on it. Since the problem occurred recently, there was a problem with that prop.

[KSmith]

Who knows what kind of damage that the 13x13 prop had on it. Since the problem occurred recently, there was a problem with that prop.

True Dat ^^^^^

[outback98]

I have an 98 outback with a new acme prop and I hit 48 mph in smooth water, with gps, half a tank of gas, and 1 other passenger. It was a test pass after I installed the new prop.