XR6 loss of power at full speed

[Pillager]

I have a 2003 XR6 with a recurring problem, although it does not happen every time out. Yesterday it happened with some regularity and as bad as I've ever had it.

I get into a run at full throttle for several miles where I trim up as much as I can for maximum speed. Going along fine and then the engine just bogs down, seems to go into a protective mode, and the prop, if spinning at all, is very slow. It just suddenly loses all bite, comes down off plane and my wake washes up over the transom. It is as if I just pulled back on the throttle and pulled it out of gear suddenly. I have to take it out of gear and let it sit a few seconds. Then I can re-engage and take off, but once this starts if I get back up on plane and try to run full speed it will happen again very quickly. If I run at less than full speed, say 4000 rpm (Iv'e tried up to about 4500 with no problem), it will run fine.

Sometimes the water stream is just about non existent just after this happens and then the stream starts up again full force. I'm not too surprised at this since there is a lot of turbulence that backwashes around the motor when this occurs.

I had it in the shop and they ran it in a pool and on a dynamometer for over an hour and could not duplicate the problem.

Yesterday when it happened (it hadn't happened for 4 trips since I had it in the shop) I played with it a bit. It was on a return trip from my second fishing spot so I had already had it on a couple fairly long runs. Once it let go, if I backed off on the throttle but didn't take it out of gear and then pushed back down on the throttle, it sounded a bit like the motor was missing very so many turns of the crank shaft. It was not a constant every turn around miss.

Anybody have any ideas?

Greatly appreciated.

[blackram]

bump back to the top.... may have got missed.

I have an 03 also. May be time to replace fuel lines, primer bulb, and fuel filter. Couldn't hurt. Look for any small leakes. They can be a nightmare.

Have your serial number ready for Don or Sherm to help you

[EuropeanAM]

A good starting point would be to READ THROUGH the following post- and follow the recommendations provided.

Could be as simple as a fuel starvation problem (hence when you back down on the throttle, fuel demand is lower, and the problem doesn't occur):

http://www.bbcboards.net/zerot...first

[Gitzit1179]

How did u make out? I am having the same probs with my Merc 150 hp EFI.

[Pillager]

Not sure yet. Between discussions and also the Merc Tech calling Mercury, seems to be a fuel problem as in not enough fuel boggs it out. It recovers quickly. Had fuel pump rebuilt, will find out Sunday I think.

[Sabre1]

I had the same problem with a 2003 XR6. I replaced the fuel line, bulb, and fuel filter and it hasn't given me any issues since. Make sure you use the new fuel lines that resist ethanol.

[Pillager]

trying something...

Video

Quick Time Video plays it for me


Can anyone tell if this is a spun prop hub? The prop people say they don't think so. I took the prop in to be re-hubed. Also had a suggestion it could be shifter cable adjustment.

At this point, I really just wish someone knew what it was so I could get it fixed!

[EuropeanAM]

That "could" be a spun hub. Remove the prop and INSPECT the hub.

If it's a flo-thru torque hub kit... you can actually REMOVE the delrin (plastic) sleeve to check it.

[Pillager]

I'm having the prop re-hubbed and I have a spare that didn't have a hub I'm having one pressed in as well. But they said they didn't think the prop was spun. It sure LOOKS like something is wrong with the rubber in there to me. check out this picture... http://www.chestercountybassma...pos=0

[EuropeanAM]

Looks spun to me.....

[blackram]

I think there is a way you can put a mark on the prop and one on the hub so that they align. Run the boat and come back and see if they are still aligned. If not, spun prop

[EuropeanAM]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by blackram &raquo;</td></tr><tr><td class="quote">I think there is a way you can put a mark on the prop and one on the hub so that they align. Run the boat and come back and see if they are still aligned. If not, spun prop</td></tr></table>

Paint pen works quite well (just be sure to let the paint dry).

[Pillager]

So it turns out it was definitely a spun hub. Got the hub cooked out, put in a hub kit, and good to go.

[lazypengu1n]

@Pillager - I signed up just so I could thank you. I have the exact same issue with a boat I just bought, same motor different hull. I was able to go at 8-10mph at 4k rpm in pretty choppy seas. I opened her up and the motor slips, I had to back down the rpm back to 4k and it would be fine. I was about 10 miles out and limped back to port. By the time I got back, I couldn't pull anything over 3k.

I'm glad you posted up the video so we all can see what the exact issue was. It has helped me out a lot because I was starting to get a sinking feeling there might be an issue with the lower unit.

I'm going to have the prop inspected repaired / replaced. I am running a 48-16318 21P. What prop are you running?

Best,
John