Am I underpowered??
 

Okay, here is the skinny. I have a 200 Diablo with a 5.0 V8 with a Alpha 1 drive. I live in Northern WY and do most of my boating on a lake that is at or near 5,000 ft. elevation. Just today we were out boating and with just my two small kids and wife at the helm, the boat was unable to get me out of the water on one ski. Just a few days ago with two more adults and two small kids in the boat I was able to get out after sucking in most of the lake water in my nose.

I have three props 18 pitch SS, 18 pitch 4 blade, and a 15 pitch, blade as well. I really don't see too much difference in RPM when I hit it, most of the time it barely gets to 4000 rpms. When cruising with the 18p SS blade, at WOT I'm around 4500 and it runs great around 40mph (gauge). the 15p gives me a little more rpm, but was uable to provide enough punch to get me out of the water.

Is this an engine issue (it runs great, no sputtering, cutouts, etc)? Is elevation just sapping my power? Is the engine tired?? Please help me out:(. I used to get out of the water behind an old Seaswirl with a 4.3 no problem. Any advise would be greatly appeciated. Thanks. ( Sorry this is soo long):shakehead:

Craig

Re: Am I underpowered??
 

Re: Am I underpowered??
 

With a 15 pitch, you should easily be able to hit your RPM limiter. I think there's more going on here. Some may be sick of hearing me say this, but it's from my own experience - do you have any knocking or engine "growl"? Your gimbal bearing could be bad and robbing you of power.

Re: Am I underpowered??
 

Indykoch,
The interesting thing about all of this is there hasn't been any unusual sounds coming from the motor. It sounds pretty tight. It is pretty hard starting the first time I start it, however, throughout the day it then cranks right up. I haven't had a chance to check the plugs, hoping to do that tonight or tomorrow night. Thanks for the help, much appreciated.

Re: Am I underpowered??
 

Check your props to make sure they haven't spun the rubber bushings. I had the same problem until the bushing finally gave way completely and I could only idle my way back to the dock.

Re: Am I underpowered??
 

I was concerned about this. How do I check them, what would they look like if they are worn out or what would the look like if they are okay? Thanks for the advice. Craig

Re: Am I underpowered??
 

If they haven't completely spun out it is really hard to see. I sent mine out to a propeller repair shop here in Florida as the cost of rebushing it was only around $70 and took 2 days.

Here's a link to Michigan Wheels repair locations.

Good luck

Re: Am I underpowered??
 

A spun drive bushing will raise RPMs with little change in MPH so it is probably not the bushing.

Are the props in good condition? No dings or missing chunks are there? Bent or unbalanced props create turbulance that could be slowing you down.

The anchor isn't dragging is it? How about weight load... try lightening the load by taking out the extra coolers and stowed anvils:D and see if it performs better.

Have you thought about going on a diet?:rolling_laugh:

You could always install Smart Tabs 'cuz they seem to help to get on plane faster.:wink_thumbup: (And Mikeyt likes them)

Re: Am I underpowered??
 

Har, Har:yes_grin: Yes, I'm considering the diet piece, but not until summer is over! I have checked and re-checked bowlines to make sure I'm not dragging an anchor... or the trailer for that matter.

Spoke to a Mercury tech this a.m. and he thinks it has something to do with the moter. They have a dyno machine and will hook it up and see if there is issues there. Could be a bit pricey though. I'll keep you posted and in the meantime stick to salads and Lite beer.

Craig

Re: Am I underpowered??
 

Just throwing this out here but you mentioned a hard start. If it has a distibutor and is not fuel injected the timing being too advanced will cause this. The plug tries to fire on the up stroke and jam the piston back down too early. It almost cranks like a weak battery. You will get great gas mileage but poor HP.

A lake at 5000ft I am still trying to get my head around that one. There must be one hell of a water fall somewhere. Good Luck with the motor gremlins.

Re: Am I underpowered??
 

Craig,

I don't believe what you are experiencing is because of the altitude. Although you and I don't get to see the performance most other do - I'm in Montana and the lakes around here are 3000, 4000, and 6400, and YES elevation does sap power. There's just not as many of those O2 molecules around to burn in the combustion chamber. I have a '95 Shabah Z202 with 5.7EFI and use different props at the different elevations. At 3000ft I run a 21P prop and run the engine at 4900rpm and get 49mph. At 6400ft I run a 17P prop and run the engine at 4600rpm and get 43mph. An engine is basically an air pump, so I would check the spark arrestor and see if its clear. Sounds to me like the engine is starving for air - otherwise your 15P should get you out of the water just fine, should let your engine run to at least 4500, but your top end will be down (pull you on the one ski fine but I think you're going to be snorting water if you want to try it barefoot).

Good Luck! Jason

Re: Am I underpowered??
 

Hey. I have a 1996 25 ft Shabah,454, brovo 3 that I run at 5500 ft in Utah. Handles 5500 about like 3600 at Lake Powell. Not that much differance. Great performing boat.

Re: Am I underpowered??
 

Did you ever get this in to the Tech> If so, what were the results?

Just curious.

Re: Am I underpowered??
 

I never did get it in to the Mercury guy, too much month at the end of money. I'm hoping to get it in sometime over the winter months and see if they can figure it out. i did discover that my prop shaft is a bit out of round, however, guys that I have talked to don't think that would be robbing power. Hope to get if figured out before next summer that's for sure. Thanks for the reply, I'll be sure to post once I find out.

Kitto

Re: Am I underpowered??
 

Well, I got word about my Diablo today and it looks promising. As I mentioned last fall the prop shaft was bent so that was repaired first. They put the boat on the dyno and they confirmed what I was thinking. Bad bog and not turning out the horse power. The changed out the distributor cap (as one of the Mariah intelligencia pointed out, thanks Greencanuck!) and plugs. As well the timing was off. After all the fixes they said she is turning out plenty of horses and should feel like a new boat. :yes_grin:

Now if the ice would go out I'd be in heaven. So...thanks to those who contributed their thoughts and help. Can't wait to get on the water.

Craig:yes_grin:

Re: Am I underpowered??
 

My boat seems to have more trouble every year to pull my brother and myself up on one ski.

Not sure if it's the boat or the fact we're in our 50's now!

My brother blames the boat. :yes_grin:

Smart tabs may help as well as moving your load to the bow to plane sooner.

Re: Am I underpowered??
 

Assuming it has a distributor, check that the advance weights move freely and are not stuck due to rust. Also, if it has a distributor with points, check to make sure the contacts have no oil film on them. This used to happen regularly on my 1987 and just dragging some paper towel throught the points would solve to the low power/RPM problem.
Lastly, check the fuel filter and fuel pump pressure, you may be running out of fuel at higher RPMs.

Re: Am I underpowered??
 

Ya gotta stay away from those Big Macs.... :rolling_laugh:

Re: Am I underpowered??
 

Have you noticed the weight distribution of persons and gear in the boat? You don't want to have everyone all seated in the stern area. Distribute the weight evenly in the bow as well to aid in plaining.

You did not mention the name of the props?

Thanks

Re: Am I underpowered??
 

Yeah, we have moved people and gear, however, the last time I tried to ski it was only my wife and two small children in the boat. I have a Stiletto prop that is 18 pitch and a Mercury 15 pitch, not sure the exact name is.

I think the main issues were addressed now though, being the timing off, new distributor, plugs, and new prop shaft. Have you found significant performance differences in prop brands?? I would be interested in what to stay away from if there is big differences.

Appreciate the thoughts.

Craig

subsequently I'm also working on the personal weight issue as well:yes_grin:..now that I think about it, I won't know now which mod actually worked:shakehead: