08 250 Pro XS sluggish out the hole and 5k RPM at WOT...

[cdc2010]

S/N: 1B457630
Dec 2006
250XS L

Yesterday out of the blue I notice the boat (Ranger z21) is a little sluggish out of the hole. (Normally it will push you back in your seat if you lay on the throttle.) Sounds fine and everything and I get it up to 53-55 mph but that's at WOT and I normally don't have to have it wide open to get to the low 50's. Also, I'm only hitting a little above 5k RPMs at WOT. Honestly, I haven't noticed what the WOT RPMs were before since I didn't run it wide open hardly ever.

I am running fresh ethanol-free fuel, I always use Don's cocktail in every tank. Plugs were changed in Oct 19.

Other than what I describe above, the motor starts fine, sounds fine idling and when running, etc.

Advice?

Thanks!

[cdc2010]

I went and got a timing light to check if it was a coil issue. The timing light blinked on all 6 plug wires.

Not sure where to go from here...

[hoytkimbershimano]

Interesting. I have an 09 Z21 and feel like mine has lost a step or 2 as well. It was never a fast boat, but hit 65 one time. Couldn’t see that happening now with my current setup...but it runs mid 50s comfortably. I have a Trophy prop. Are you sure you don’t have any water trapped in the bilge anywhere?

good luck!

[Savage]

Air and fuel pressure testing is next.

[cdc2010]

Interesting. I have an 09 Z21 and feel like mine has lost a step or 2 as well. It was never a fast boat, but hit 65 one time. Couldn’t see that happening now with my current setup...but it runs mid 50s comfortably. I have a Trophy prop. Are you sure you don’t have any water trapped in the bilge anywhere?

good luck!

I'll check to see if there's water anywhere. We are coming off a huge rain, but I drained the boat at the ramp before I launched. Maybe I didn't get it all. I'd love for it to be an easy answer like that!

By the way, what type of RPM do you get at WOT in your z21?

[hoytkimbershimano]

I did a quick run with myself and ab adult passenger with pretty low fuel. We hit 59.5 mph @ 5200ish RPM. My hotfoot was pegged. I could have gotten a little more with some trim, but not much. I have a manual jack plate and have never touched it. It was also hot (90) and humid. My boat just seems so happy running 45 mph around 4100 rpms and handles a moderate chop like nothing that I have never been inclined to change it. I would not mind trying a tempest or bravo 1xs prop...

Just to be clear - I don’t think I have a problem other than an aging boat and engine and a top end that I’ve never dialed in. I spent the last week pulling 3 kids (same time) around on a large tube with no problems!

tim

[cdc2010]

I did a quick run with myself and ab adult passenger with pretty low fuel. We hit 59.5 mph @ 5200ish RPM. My hotfoot was pegged. I could have gotten a little more with some trim, but not much. I have a manual jack plate and have never touched it. It was also hot (90) and humid. My boat just seems so happy running 45 mph around 4100 rpms and handles a moderate chop like nothing that I have never been inclined to change it. I would not mind trying a tempest or bravo 1xs prop...

Just to be clear - I don’t think I have a problem other than an aging boat and engine and a top end that I’ve never dialed in. I spent the last week pulling 3 kids (same time) around on a large tube with no problems!

tim

Actually, that makes me feel better. I had me and another 200 lb man on board and about 25 gallons of fuel (which is more than normal). It was hot and humid as well. I had my hydraulic jackplate in its normal position and had it trimmed up high like normal when wide open.

I just didn't know if 5000 RPM at WOT was normal or not. I did notice that I could reduce the throttle to about 45 mph and quickly hit it wide open and it would surge to 55 pretty nicely. Hmmm...

[lpugh]

it is not not normal, need at least 5600 RPM. Prefer 5900 to 6000 at WOT trimmed out. I think you need to get this checked by a Merc dealer, Don't risk damage to the motor

[hoytkimbershimano]

Going along with Leon’s comment —- I know that my setup never got me to max RPM at WOT. If yours did and now it does not, you should continue to see if there is a problem. I definitely see a difference in hole shot with number of passengers and temp:humidity.

[EuropeanAM]

Second to Leon's advice. And need to start with the BASICS: Compression Test, Spark Test (when hot), Fuel Quality, CORRECT OCTANE, Delivery and Air/Fuel Pressure Tests.

[cdc2010]

I've taken it back out twice since my original post. There was a good bit of water in the bilge area from some heavy rains (even though I drained it for quite a while before we took off the other day). The carpet and everything had time to dry out. I went out alone both times and both times it was quite windy.

The hole shot seemed very snappy and normal to me this time. At WOT, I got it to the upper 5300's in RPMs easily. It was so windy I had to run in a large cove rather than the main lake, so I didn't have a lot of room or time to tweak the trim and get all I could out of it. I do think I could have gotten some more RPM out of it but cannot be sure.

I will keep an eye on it and test again when the main lake is calmer to see just how much RPM I can get. But right now it feels no different than it has the whole time I've owned it.

[EuropeanAM]

Good to hear. A couple sunny days parked nose-high on a hill with everything opened up will continue to do a lot of good.