A change of set up


Well-Known Member
When we re-launched our restored Greavette in 2012, there were some teething problems that had to be solved. The largest was an overheating issue in the I6 250cid 165HP Mercruiser. After a summer of attempts and a bucket of $ (more than a couple thousand) the decision was made to repower.

for 2013, most here know I built a 4.3L V6 from the crank out and "hot-rodded" it a little bit to the point where it makes 237HP / 274TQ. I also decided to change the sterndrive from a 1.65:1 pre-alpha to a 1.47:1 Alpha One and settled on a 19p High Five 13.25" diameter prop.

So, again 2013 was about teething and prop issues (as will be with a new set up) but, by the end of summer she was running pretty well although, I still had issues to contend with. 2014 saw a crappy summer for weather and we hardly got on the water, save for six times. I didn't mess with the boat as I wanted to go boating... At haul out I noticed the plugs read rich and I knew we still did not have the optimum prop on the boat.

2015 started out with some hull leaking issues as the woodwork restoration shop used the wrong sealant in some crucial areas. That fixed, I moved to a hotter plug in the engine and went to have a fantastic summer of boating. The Greavette planes out quickly, is very responsive and tops out at 50.1 MPH (GPS).

The issue is that the engine will only pull 4,100rpm. It's been dyno'd to 5,300 and Mercury specs 4,800 so, we are still not right. I have tried re-propping however my options are limited and every prop we tried showed less performance. I winterized the boat 2 weeks ago and tucked her away till spring.

At this point, I have decided to make a change in the gearbox of the Alpha One, moving from a 1:47:1 ratio to a 1.62:1 in hopes of raising the RPM to the optimum. The added bonus is that now I will also have a wider selection of props to try. I really like the High Five and hopefully the new gearing will spin the current 19p prop to 5,100 or so RPM.

Making the gear change is NOT an inexpensive proposition. Even though I have a good price on the gear set ($450) the labour to do this swap is another $500. Considering another stainless prop might be in order the hole in my bank account will still grow. But, if it solves the issue it will all be worth it. The gears arrived this week.

In addition, 2016 ACBS boat show in Gravenhurst is featuring Greavette boats. So, I have committed to a new varnish job in the spring.... just another $1,000 or so. I'll keep everyone posted on how we progress. :)