pro motor durability

[Tim Weber]

I wanted to hear from some of the guru's out there what was going on at Depue.

I have never seen so many motors go up in smoke. I think 350 runabout had 12 entries and 7 of the 12 didn't finish the 1st heat. I know David Mitchell stuck his 250 3 times.

Did Rossi or VRP change something in the motors?

Tim

[David Weaver]

My Experience

Tim,

For many reasons, there is always higher than average engine failure at the PRO nationals in DePue. The lake is shallower in July generally and the sediment from the bottom is pulled up. I believe this increases the water density (making the engines work harder) and run hotter. Also, people are pushing the envelope on jetting and props, resulting in a lot of sticks.

The shallow water also creates more wave action and turn 2 becomes very rough. Boats launch into the air, landing hard. This is tough on cranks and lower units.

Further, for a number of racers this was their first event of the season. Not suprisingly, many of these individuals had a difficult weekend.

I thought the attrition in 125 hydro was very lite considering how hard the 1 cylinder engines work.

Input from others?

[diamondprohydro]

I have had 2 Rossi's since 2003 and have only stuck each one once (one this year just before the race). DePue has alwasy done funny things to me like people running into me, boat breakage, and especially lower unit damage. The rest of the time they run like a champ. I did however chase an electrical (MSD) problem this year but have that fixed.

DePue is just Depue. Gotta love the challenge.

[David Weaver]

At 13,440 RPM's

You probably are going to burn pistons and wear out cranks. I guess you have decide if the ride is worth it or not. Attrition and maintenance are and will always be part of PRO racing. A set-up that completes heats can overcome a faster set-up that leads to early engine failures. Doing your homework and maintenance are important, as is the manner in which one drives the boat. The reward can be a great ride!!

T. Ziemer photograph

[seanp3]

The water temp at Depue felt like a bathtub. It was very warm. I'm sure Depue was a little harder on equipment than normal from this as well

[Tim Weber]

I didn't know that water temp was such a big deal with the new stuff. I was under the impression that if you ran too lean you would tear up motors.

How do you compensate for warm water? With the worlds coming to Florida in October the water will be pretty toasty. Maybe run a big prop to keep RPM down?

[seanp3]

We just ran the OSY400 class, which we ended up running the Yamato a little deeper than we normally do to make sure we were pumping plenty of water for the cooling.

[bill van steenwyk]

It Is Not Hard To Figure Out

There is always a high failure rate of engines, boats, props, drivers, etc., at DePue and always has been since I first went there in 1968. What you all need to remember is it is the NATIONALS, and everything is run on the ragged edge, engine tuning wise, setup wise, pushing the clock, and every other way, if you intend to win and not just "also ran". All the other excuses are on the front and back of the "Boat Racers Excuses" T shirts sold several years ago.


Repeat, ITS THE NATIONALS. It all starts there if you want to be considered for the HOC. Everything is pushed to the limit. It's not hard to figure out.....

[David Weaver]

Found one Cause

I started unpacking and cleaning the trailer from the Nationals. In my waste/replace bag was a check valve that began failing to hold presure. I believe that this check valve cost me 3 burned pistons between Constantine and DePue. The $2 part would work for a while and then randomly fail. I did not pick up on it, until I switched powerheads and the check valve failed to hold on the beach. So, moral of the story. Change the $2 part often!

[Lights]

check Valves

David, put two of them $2.00 check valves on. One is good but two gives you some insurence.

[Dave_E71]

Was thinking last night and I believe I had 68 heats on the nikasil and pistons, 48 on the crank and 20 on the rings before a complete rebuild on mt 250. It was still pretty strong last season but I had to finesse the pipes rather than slamming them home and I was a little down on top end towards the end.
The 125 is a different story, they are far more unforgiving. I know that if I get greedy on the jetting, I WILL be replacing a piston....
Knock on wood, we've been lucky in that we haven't had the catastrophic failures that others have seen.

Dave