1999 Sport Nautique with GT-40
- Jeff Carroll
- Nov 25, 2025
- 1 min read
Sort the comments below by OLDEST to see a chronological timeline of the work we have completed so far.
A client from Pennsylvania brought this vessel to us in hopes that we could figure out a miss that was occurring in his engine. Another shop had done extensive work on the engine after an unfortunate electrical issue, but the engine still isn't running quite right. We'll do our best to track down the issue, and fix a few other little things along the way.
The new fender is on, and the side steps of the trailer have been securely welded into place properly. A crack in the trailer frame was also found and welded. Glad that was noticed!
New harmonic balancer is on. No pictures (I forgot to get them before the installation), but it is ready for a water test and timing adjustment now, finally.
This boat's trailer was missing a fender when it arrived, and the owner asked us to replace it. We ordered the replacement from Boatmate, but unfortunately the whole side step area needs to be rewelded before we can mount the new fender. We'll have that done and then get this installed.
We think we found the reason the timing was out of spec. The harmonic balancer (which is where the timing marks are) has failed. We noticed a shake to the engine, and when we looked further into it, the rubber had failed. Of course you can't get new ones anymore, so this one was sent out for rebuild.
Here's the original:
We ran this boat on the hose today, and tested all of the normal suspects for engine miss on a GT-40. We found that the timing was SEVERELY out-of-spec. Often, people not used to working on a GT-40 forget (or don't know) that you have to disconnect the spout plug (small connector near the distributor) in order to get a proper timing reading. Once the timing was set properly, it seemed to run much better on the hose, but the true test will come with a real lake test. Unfortunately it is raining today, and it is going to be quite cold and windy tomorrow. That means the water test will have to wait until next week, this Thursday …