Im a new EPIC owner, but I have low RPM and MPH at WOT - please advise

[EpicMT]

How do I confirm that there is no slack in the throttle cable? I only get 4700 rpm and 33 mph at WOT at 6100 feet altitude and brand new acme 3 blade 13x10.5 prop. New plugs, clean MAF, clean fuel filter. May have had old fuel, but it seems to run smoothly without bogging down or hesitating. I also have a bright drive temp light (even though the analog temp guage is only at 170) and a dim check engine light (which did not throw a code).  Are there any simple things i can do to troubleshoot? Do you think my tachometer is wrong? Should I drop to the 13x9 prop - Acme guy thinks I have an engine problem that I should rectify before propping down again. I also had a recommendation that i should change the gear ratio from 1:1.25 to 1:1.46 by switching out the v drive, which seems like overkill to me.  How can I confirm that I'm not at a 1:1 gear ratio?  If I'm at 1:1, then I may be over-propped.

Do you think that this Is a throttle lever sensor issue or a loose throttle cable or bad gas with clogged filters?

I have read many posts on this forum re limp mode and throttle issues and I think I may be having those problems, but I do get consistent power increase from 12 through 9 on the throttle (I just don't seem to get any increase in power from 9 to 7, which is WOT). I'm troubled by this because I searched for years for an s22, found one I like, bought it two weeks ago and now I'm not getting same rom and moh performance as others on this forum. It only has 250 hours. Please advise. Thanks.

[Water Sports]

Slack in cable is unlikely do to low hours, remove cable from throttle body, leaving the outside bolted down, and move the hand throttle while holding the end of cable, everything should move uniformly.  Reconnect the cable, now take your air intake off and manually move the throttle  all the way to make sure butterfly moves from 9 to 7.
 
Is it the red light in the middle of the dash?    You can test components of throttle body, page SF 31-32 in the repair manual.  Does not sound like limp mode.  What spark plugs are being used?  Don't go cheap, good plugs, high end gas.  Your tranny is good for a life time. 

[EpicMT]

Thanks, WS, for your Comments and recommendations; thanks, Lesman and Brad, for your help in connection with my propping questions; and a huge thanks to Derek for walking me through several troubleshooting scenarios. I'll troubleshoot throttle components tonight and tomorrow and let you know what I discover. 

The red light is in the middle of the dash. Bright red drive temp light and dim red check engine light.  The local shop put in high end plugs last week, but I ran it with last year's gas with the new plugs. The motor sounds and feels smooth at idle and at WOT, but the gas was definitely old. Would old gas contribute to low speeds and low rpm? I recently put 91 octane (with 10% ethanol) in the tank. Is that sufficient moving forward or do I need to find 93 octane?  I don't think I can get gas without ethanol nowadays. 

[ktdust]

Our boats don't like ethanol so if the gas you're using has ethanol in it, try using blue Sta-bil. It will help the engine burn the fuel. 91 or 93 octane shouldn't make a difference. I use 91 or 94 depending what Chevron I go to.

[toyotafreak]

I used to worry a bunch about old gas, but really I think it's more just hard on the plugs when I let her sit too long without running. Anxious to hear what you find/found.

Basic question in my mind from our conversations was really just how much power do you lose with altitude. You've got some significant altitude there.

[breakawaydaze]

I saw where you cleaned the mass air flow sensor and the fuel filter and replaced the plugs...but did you clean the flame arrestor?  It looks like an air filter at end of intake.  I clean mine twice a year.  It gets all kinds of belt debris, carpet fuzz and other junk in there.  Some of your problem sounds like airflow issue.

[EpicMT]

Thanks again for the suggestions. Do you have a picture of, or can you point me to the page in the manual regarding, the flame arrestor? I'm unsure if it was cleaned during the tune up. Thanks.

[breakawaydaze]

its in the maintenance section.  Its listed as a "spark arrestor"  easy to get to, easy to remove, easy to clean and if it is full off gunk, you should notice a big improvement.

Go to this pdf and go to page 18. Pictures and Instructions.  Same process for Direct or V-Drive

http://www.epicmarine.com/docs/Epic%20v-drive%20annual%20maintenance.pdf

[Mudwheelin]

It sounds like limp mode.. This happend on my 1999 , the throttle cable is not directly attached to the throttle cable it is attached to a throttle pedal position sensor which then tells the throttle motor how far to open the throttle .. When the throttle motor is inop you only get a small amount of this .. Which sounds like what's happenning to you.. Get a throttle body off a 98-00 ls 400 or gs 400 paint it before you put it on and that should fix it

[wakejunky]

"a dim check engine light (which did not throw a code)." How do you know it didn't throw a code? did you rent rick's scanner? we do have a scanner available now. its silly to just replace the entire throttle body when you can just replace one of the sensors on it. If that is even your problem. There is about 100 different codes these engine's can throw and its not just throttle body issues that will put it in limp mode. 4700 rpm doesn't sound like limp mode to me. you have a very aggressive prop not to mention your at 6100 feet. do you wakeboard only? i do and that's the only reason to have an aggressive prop like that. i think you do have an engine issue, but depending on what you use the boat for you may be over propped as well

[EpicMT]

Thanks, WJ.  The local shop has a scanner and no codes were stored. I actually tried a more aggressive prop yesterday, which is an acme 3 blade 13x9 with a .060 cup, and which resulted in 5600 rpm and 33 mph (non gps) at WOT. Is that the best I can expect at 6100 feet of elevation?

This data appears to support the advice I received initially to move from a 1.21 gear ratio to a 1.46 by switching out the v drive. This advice was primarily driven by the elevation of our local lakes. I'd love to see this boat at low elevation.

[wakejunky]

wow i didn't know acme made a 13x9 that is crazy aggressive. do you have the original prop? what is it? Try swapping to it. you certainly do not need to switch your vdrive. you just need to find the right prop. the lower the number the slower max speed will be. I have a 13x11.50 on a 1.46 ratio v drive and i can not go over 40 mph at wide open throttle. I'm at 400 ft elevation though. my original prop would let me easily hit 50 mph, but my hole shot was crap. i only wakeboard so its worth the loss to me.
special software is needed to communicate with the epic's computer, just any scanner will not work. most generic obd2 scanners just say "no connection" or something like that. Also if you disconnect the battery or cycle the perko switch the codes will be erased. i would disconnect say the MAF sensor and see if the scanner your using detects the failure. if so your golden if not start at square one.

[EpicMT]

Thanks again. My original prop is a 13x14 OJ, which is worthless at high elevation (the boat hardly gets on plane). My s22 was originally at sea level, which explains the less aggressive oem prop.  The 13x9 is a rocket ship out of the hole, but fairly low top end speed, which I'm fine with. It seems that with my 1.21 ratio v drive, 13x9 prop and 6100' elevation I'm getting similar results to your 1.46, 13x11.5 and 400' elevation.

I believe I cycled the perko switch before checking the code, but I haven't had a check engine light since, and, now that I'm getting 5600 rpm, I think the engine is performing well.

[wakejunky]

i agree. Enjoy that new boat

[brad]

Had some issues at Flaming Gorge a few weeks back - no power between 3,000 and 4,000 rpm (couldn't hold speed to wakesurf).  Seemed fine below or above those rpms.  Ended up taking the flame arrestor/air filter off and things improved for the rest of the week.

Came home and decided to clean the flame arrestor/air filter (which I do each year when I winterize) also decided to clean the MAF sensor (never cleaned this before).  I removed the MAF sensor from the air intake housing.  Used some throttle body cleaner.

Took the boat out today at Utah Lake and wow.  Consistent power through out the rpm range.  Lot's more power as well.  Must have been a few years since I remember this kind of performance.  My son even pulled the tow rope out of my hands because he wasn't used to the extra power.

Guess I'll add the MAF sensor each year to my maintenance/winterize routine;-)