Slow ss2000 comp

[St]

Hi, bought myself a ss2000 with merc 2.5 EFI 280 this sunmer. I have ordered a 30" Lightning et and is still waiting to get it. Meanwhile i dont own another prop so I borrowed a 27" Tempest plus from a friend just be able to use the boat right now.

Im really worried about the lack of performance becausen I cant get the boat past 90 no matter how I trim the motor. I also reach the same speed regardless if my brother comes along in the boat. Always stops just below 90 mph at 6900 rpm. Engine height is prop shaft just above bottom of boat. Im aldo a bit disapointed of the avceleration.

I know this is not the prop for this boat, but should I be worried about the engine? Shouldn't the boat be faster even though using the wrong prop? I was expecting to turn at least 7500-8000 rpm with a 27".

 

[K.Kiser]

Almost sounds like a 225 promax hitting the limiter..? A healthy in-tune 280 should rev the heck out of that prop and bang it off the limiter in excess of 100 mph with snappy acceleration.. What's the boat running like in regard to obeying trim input, handling, etc..

 

[xb03]

Do you have any pics of the motor?

 

[St]

Thank you for responding!

Dont have a picture to post at the moment while I'm in my parents summer house. The serial number and ecu are all 280 hp so even though it sounds like a 225 it actually is a 280. Whats weird is that the engine sounds and run perfectly slooth at all speeds. Starts super easy and idles perfect. I have had bad engines before and this one really dorsn't sound like one.

This is the only Allison I have driven and therefore its hard for me to analyze handling, but to me it handles very good. Almost no bowlift before 50 and then when climbing up on the pad the boat comes lose and the bowlift is great.

Is there any posibility its the prop that is super weird? Its not in the best shape? I gurss getting my new et will be the judgement day. :/

 

[Bobalouie]

It almost sounds like you are not all the way up on the pad yet. Mine acts like that if I have it trimmed too low and have too much hull in the water. It just stops pulling at around 90 mph and right around the same RPMs. It feels free, but its not. Be careful and pay attention to what the boat is doing, and maybe give it another bump once you get to the point it stops pulling and see what it does.

 

[jas638]

[QUOTE=St

 

[patches]

Have you checked to see if the motor is at full throttle when the pedal is all the way down. The butterfly should be perfectly horizontal in the horn

 

[St]

Thanks once again!

Bob, I will give the trimbutton some workout and see what happens. Got my lightning et yesterday and once the wind calms down I will test it.

jas638, thank you for the input. If im not satisfied with the new prop I will keep that in mind. At the moment Im not concerned about the handling though, but maybe later?.

Patches, I will check it out right away!

Thank you guys!

 

[St]

Missed one part, regardkng the eingine height the propshaft is just a bit over the pad. Havent measured but thought it was a pretty good startong point while the previous owner ran it lika that.

 

[Bobalouie]

There is nothing wrong with running above the pad, but if this is your first Allison, you might take some accurate measurements to find out where you are and go back to even with the pad. It will make it easier to learn. I dont think I would run lower than that though. You might have the engine too high and you are losing trim responsiveness.

Mine was like that when I first got it because I was running the previous owner's setup of a 7" jackplate and 1/8" above the pad with the propshaft. It was good for him, because he was about 75lbs lighter than me and didnt run with a troller very often. Once I went back to even and fixed the fat butt issue with more setback, it became a whole new boat. It just felt better, the bow responded to trim better, and it ran much more free.

 

[K.Kiser]

Depending on the pad lip dimension of an SS2000, above the pad may be a little high but you'll notice it in the handling if it is.. I'd use at least 8" setback..

 

[St]

Thanks very much so far!

This is what I have found since got my 30" lightning et:

-No matter if i trim the engine out as hell, run it straight or anything in between the boat stops pulling at 98 mph (I am a very experienced driver so no problems with handling what so ever). The fastest run was when I trimmed out like crazy (a lot more than what should be optimal but it still went faster like that compared to when running with a better angle). If i have a passenger or not doesnt matter. It still runs exactly the same top speed is always 97-98 mph. :S

The engine runs super smooth and i simply cant belive there is something wrong with it.

Regarding the engine height I really dont know how to do an exact messure because the small bottom wheel wheel from the trailer comes in the way? I can see with my eyes that the prop shaft is somewhere between: even with pad - 0,5 inch above.

Is it possible my engine height alone could be the reason for the lack of speed? Is it possible a 1/4 inch adjustment could gice me the 15 mph give or take that is missing?

 

[patches]

Did you check for wide open throttle?

Level the boat on the trailer using the jack. Put a level on the pad of the boat to make sure it's perfectly level, make sure when checking it that you're not laying the level on the lip of the pad. Stay about a foot forward of the very rear of the pad
Next pull your prop and put a small level on the propshaft and get it perfectly level using the trim
Now that you have the boat and propshaft perfect you need a long level or a straight board to lay under the rear of the boat running from under the rear of the pad to under the propshaft. Probably need at least 4 ft. Level up the board or level, whatever you use, and measure down from the pad(not the lip at the rear of the pad) to your board/level. Then measure from the level/board to the center of the propshaft.
Just for example, you may have 16" from the level to the pad and 16.5" to the propshaft center. That would mean you're are .5" above the bottom. A lot of people after going through all this will get the motor perfectly even with the bottom and then mark the jackplate somehow to show even. That way you don't have to go through these steps again. You can just refer back to your mark on the plate to see how high or low you are in relationship to even

BTW, does the boat still have the lip on the pad? Should be a lip around .060" in height, give or take

 

[XXXR2001]

[QUOTE=St

 

[St]

You are awesome guys! Im the only person in the entire Sweden driving an Allison so I really appreciate all this expertise.

I did check wot, and it was a perfect 90 degrees at full throttle.

I wil try to measure the engine height properly when Im back in town. Will let you know what I find

Interesting, I do experience I have to compensate with more trim the more I push throttle. Im also experiencing some vibrations when running fast (nothing major), could that be because of the prop not running smoothed through the water due to high engine height?

I let my father videoing me running at full speed yesterday. Will ask him to send i to me and I will post here for you guys to see. Even though I am not satisfied with top speed i think still its a really fun boat to drive

 

[rmills280]

your not going to get much faster with the limiter at 7500-7800 but a 28 will probly work better. never liked the 30 et on a ss

 

[SLOmofo]

I would add to Patches post to also mark the trim guage for neutral trim. I find it eaiser to lay a 3' leval on the flywheel.
It does sound like your on the limiter though also. What does the water look like comming off the prop.
Look at Whippers pic. Skimming with no rooster tail, but it's a ugly yellow boat!
http://forum.allisonowners.com/showthread.php?t=9738&highlight=bill+smith&page=2

 

[Bobalouie]

How much setback do you have?

 

[St]

http://m.youtube.com/watch?v=seNVDjfgrEk

Upploaded a video of me at wot 98 mph. As you can se I have way to much trim and still this is the fastest run that day.Much faster than when running with less trim. 6800-6900 rpm (far away from limiter). Slip is 8% which I think is reasonable.

Will get back to you when I have had time to check pad, set back, engine height etc.

Thanks!

 

[patches]

The trim looks good. The boat is riding very wet. Interested to hear about your propshaft height, setback, and whether it still has a lip on the pad. What prop was that in the video

http://youtu.be/seNVDjfgrEk