2018 GTI SE 155 Only 5mph

[SlipperyPete]

Howdy. I purchased a 2018 GTI SE 155 last July. It only had 19 hours on it. It ran great and the kids had fun using it. We added about 11 hours on it until it was winterized and stored. It ran great I put it in the water a couple weeks ago. It starts and goes, but won't go over 5mph despite full throttle. It also sounds a little rough. I'm hoping for some advice on what to check before taking it out to get serviced somewhere. All help is appreciated!

 

[mikidymac]

Do the rpm go up to full throttle but the ski doesn't move like a slipping clutch?
If so it is either the wear-ring or impeller or both. Typically it is the wear-ring.

 

[SlipperyPete]

Thanks for your reply. The rpm's don't get very high like they would at normal full throttle. I'm going to change the spark plugs first thing this weekend. Would there be some kind of warning light or indication that a plug is bad?

 

[mkov608]

No. Have you inspected the jet pump inlet/outlet?

 

[SlipperyPete]

I haven't looked at that yet, but I'll be getting it out of the water Saturday morning and will be sure to check. My hope for this thread was to get some ideas of what to focus on when it's on the trailer. Thanks for your reply and idea. I'm guessing you are suggesting I look for any blockages?

 

[mkov608]

Correct.

 

[Milehighguy303]

Definitely change your spark plugs and then try it on the lake. Check to make sure there is no blockage in the jet pump. Hopefully 3 spark plugs is all you need - $5 each at most auto parts stores. No real warning to when plugs are bad, other than poor performance. I change mine every year or two, just to avoid any poor performance issues.