by Dave Casper


It's not often that you get the opportunity to get the engine that you have always wanted for your boat, but I was fortunate to have that chance. I have a 1983 HydroStream Vegas "V" bottom and the engine I wanted to replace was a 1993 2.5 200 Mercury. There was nothing wrong with the 200 - in fact, it was in perfect mechanical condition and I had just finished re-painting it and putting on new decals. BUT, I have always liked the '97 225 ProMax and I thought it would probably be the most ideal engine for my boat. I also like the '97 because it was the last year for the striped cowling design. And of course there's that "legal" thing about modifying engines built after '97 and I was certainly open to the idea of "warming" the engine up a little bit. There are obviously more powerful engines available, but the ProMax would give me more power than my 2.5 200 while being more suitable for my use than a 260 (the 260’s 16 amp charging system, Nikasil block, appetite for rings and general lack of user friendliness were not for me). Also, besides being able to go fast, I wanted an engine that would be able to idle at slow speeds for extended periods. A 280 would be great but is well out of my price range.

My old 1993 2.5 200 Mercury


So on to my search for an absolutely mint ProMax. I knew from my search for the 200 that finding a mint engine can take quite awhile – I finally found the 200 up in Montreal, Canada! I started by calling the people that I knew of that were the most reputable and the most likely to have an engine I wanted. I called Bob Garone, Bill Gohr, Jay Smith, Diamond Marine and others. As I talked to these people about what I was looking for in an engine, I started to get different opinions of what engine would best suit my needs. Besides the ProMax, there was a strong push for me to go with the 260 even though I had some reservations about it. Basically, I was told by some that most of my concerns such as the charging system, starting and idle characteristics, reliability, etc would be pretty much the same between both engines with the 260 possibly being the more reliable one. I have the greatest respect for the opinions of each of the people I talked to and I would not hesitate to have any of them work on my engine, but I was getting conflicting opinions on which engine would be best for me. Then one day I saw a posting by Mike Balz regarding his 260 so I wrote to him to get his opinion on the engine. Although Mike had nothing but good things to say about the 260, he suggested that I contact his engine builder – Randy Pierson. I called Randy and had a long talk with him. I was very impressed with his knowledge of engines and HydroStreams in particular. As I soon found out, I had good reason to be impressed. Randy worked closely with Howard Pipkorn from 1986 to 1991 and was deeply involved in the research, development, and testing of numerous boat designs. He came up with the ZT stage 2, 3 and 4 bottom modifications. While racing various HydroStream models, he made improvements to them – some of which resulted in production changes. From the mid 80’s to early 90’s, Randy had his own HydroStream dealership and was one of the factory’s sales leaders. Besides his experience with HydroStreams, Randy has also raced boats for many years in classes including Formula 1 tunnel boats. When he is not racing, Randy, through his company Gran Prix International, is involved in all aspects of boating: from rigging - to extensive propeller modifications - to his specialty - engine building. He even builds hi-performance snowmobile engines during those long Minnesota winters.

We discussed what I was looking for in an engine – what type of boating I wanted to do and how fast I wanted to go. I felt very comfortable (probably in part because his views went along with what I had always thought about the 225 vs. the 260) with Randy’s suggestions regarding the engine that would be the best for me - a slightly modified 225 ProMax. But just to be sure, I wanted to check one more source. I wrote to John Tiger from "Family & Performance Boating" magazine, who has been very helpful to me in the past, and asked his opinion. He knows Randy personally and agreed that the ProMax would definitely be the better choice for me. He also said that Randy had the experience and expertise to build me a good, strong, reliable engine.

Randy Pierson (rt) & Tork with Randy's Allison


Now that I knew what engine I wanted and who was going to build it, it was time to decide the exact details of the engine. After more telephone conversations, we decided on the following:

1997 ProMax powerhead with the 40 amp charging system.

Forged 2.5 race pistons with moly coating.

Chrome faced rings with pin modification, 260 silver plated bearings, "big" connecting rods with SPS bolts.

The new Boyesen 4-petal rubber coated carbon fiber reed system.

Digital ECU.

35 cc 260 cylinder heads.

Bridgeport tuner and adapter.

Removed exhaust liner.

New ProMax cowling.

Choice of gearcase – CLE, Mod VP, stock 200 with a Bob’s etc.

Oil injection removed.

The project was started in early December (2000) and I didn’t plan on delivery until sometime in March, so Randy had plenty of time to build the engine. He put that time to good use! Every time I called him he was always thinking of what would be the best things to do for my engine…everything from different types of ECU’s to his own design of an SVS type of intake system. By the time the engine was delivered, the changes made to our original plans were:

Block and exhaust chest ported to 280 specifications.

An A-17 analog ECU – this summer we will hopefully try a digital ECU, model to be determined.

Stock 37 cc 260 heads – start with this and then go to the 35 cc heads if more power is wanted.

Leave the exhaust liner in because I wanted a quiet engine but the center section was drilled and then tapped and plugged so that the exhaust could be relieved in the future if I wanted.

A JC’s "where’s the hose?" gearcase with heavy-duty components was decided on.


Various pictures of Randy's shop


Selection of propellers Gearcases


Around April the engine was ready to be shipped to me. Randy and I had made tentative arrangements to meet in Pittsburgh, PA – him with the engine and me with the boat. We were going to rig it and then do some testing. Unfortunately, our plans fell through and I thought that I would be testing on my own. Randy had different ideas though. Because we live so far apart, he wanted to see the engine run and be able to make any needed adjustments in person. He asked me to arrange the shipping and he and his partner, Gordie "Tork" Caspers (no relation) would airline in for a couple of days. Could you ask for better customer service?!?! A friend of mine in Tennessee, Jeff Young, helped arrange the shipping and saved me a bunch of money. The engine arrived in perfect shape and I had it rigged when Randy and Tork arrived. While I was inspecting it, I was impressed by the attention to detail. All the electrical connections were coated with liquid electrical tape to prevent them from coming loose. Even the sparkplug wires had their ends wire tied so they fit tightly and would also never come loose!


One of the really nice things about working with Randy was, besides his expertise building engines, his experience with HydroStreams. He made predictions as to how he thought the boat would perform. I was anxious to find out how close his estimates would be. He also made some suggestions regarding suitable propellers to try. He thought that one of the fastest props for my setup would be a 14 X 28" inline Merc chopper and that I should keep an eye out for one. I found this interesting because with my 200 I had found the 14 ½ X 28" big eared chopper worked best – the inline didn’t have enough lift. I had just bought a mint 28" chopper II that I had not even tried yet and now I had to look for another prop. But, it just so happened that I knew my local Merc dealer (Kenyon Marine, who has a ton of old parts lying around) had one sitting on his shelf in excellent condition. I went in and double-checked that it was the right serial number. Dennis, the owner, offered to let me try it out and if I wanted it I could have it for $125.00. As it turned out, Dennis never got his prop back!

After I picked up Randy and Tork at the airport, we headed out to my house to check the boat over. It was too late in the day to do any testing so we just talked about boats and motors. Randy also checked my inline prop out, fine tuned the edges, and deemed us ready to go in the morning.

Randy tuning the edges of my prop


Early the next morning, Randy, Tork, my brother Mark and I headed for the water. The weather was pretty good – sunny, about 55 degrees but a little windy with some choppy water. Randy wanted to make the first few runs in the boat to see how it handled. He told me that the Vegas varied a lot and that you could have one that runs nice and light and that will get up and go, or you could have one that runs heavy and relatively slow. So it was now time to find out how the boat with its new engine ran. And what was Randy’s prediction? Upper 80’s to 90 mph. We got the boat into the water and it started and idled perfectly. Randy then headed out and made a few passes. I must say, from the shore it looked REALLY good! When he came back in, Randy showed me on my Gaffrig GPS speedometer, using the recall function, his speed. 90 MPH! On his first time out! That was better than what I had hoped for. He also was very pleased with how my boat handled. He said it would get right up on its pad and felt nice and light – just like a slightly bigger V-King. He thought it was one of the best running Vegas’s he had ever driven. That was certainly nice to hear! I took the boat out next and noticed right away the extra power and that the boat responded well to it. I was not able to match Randy’s speed…I need a little more seat time to learn exactly what the boat likes and how to do it – Randy can just go out there and nail it. Randy and Tork took the boat out again with a different prop and then we loaded it up and headed home. Once back at my house, we checked the engine and boat over, talked about its performance and what to expect of it. Because everything worked so well the first time out, Randy and Tork decided to airline home early the next morning. I was certainly sorry to see them leave – I was learning so much from them on everything… from engine work to prop selection to boat handling.

Randy out for the first run


90 MPH its first time out!


Before they left, Randy went over with me what speed and rpm’s I could expect with the various propellers I have and how the boat would handle with them, as well as other props I might want to try. We also discussed some minor improvements I could make to the boat as far as setup.

The rest of the season both the boat and engine ran perfectly. Although it seems like I never get to take the boat out as much as I would like, I am feeling more comfortable with it and my speeds are climbing. Toward the end of the season Randy sent me a couple of his props to try to get a better idea of what the most ideal prop would be for the boat. In testing I found that Randy’s predictions of speed, rpm, and handling for each of the props I have tested were right on the money. So, I feel confident that his latest prediction of a top speed of 95 MPH will be met.

Since I saw Randy, we have remained in touch and he is still always thinking about possible improvements to try on my engine. We decided to take my 28" Chopper II and have him turn it into a Lightning ET. He did beautiful work on it and I am looking forward to trying it out. One of the things we hope to try this coming season is a digital ECU to further improve the running characteristics. We also may try some slightly milled heads for just a little more power.


R.P. Chopper II cut into Lightning ET



So how was my engine building/buying experience? Great! I can honestly say that this engine is exactly what I wanted. It is quiet, smooth running, reliable, looks great and has the power I want. I definitely made the right decision to have Randy build me the engine. He listened to what I wanted and we talked a long time about the options available to me and what would be best. Even then, up until the day the engine was shipped to me, he was always thinking about possible improvements and better ways to do things. His expertise with HydroStreams and their setup was certainly appreciated, as was all his advice. I would HIGHLY recommend to anyone that wants to have some work done to their engine or is looking for a new hi-performance engine to give Randy a call – I think you will be very happy with the results.

I want to take this opportunity to thank the people who helped to make this possible. Thanks to: John Tiger who has taken the time to answer my many questions and Steve Anderson for providing some of these pictures. Special thanks to: Balzy for putting me in touch with Randy. Jeff Young in Tennessee for all the work he did helping me ship my engines. And extra special thanks to Randy Pierson for building me my "perfect" engine.

Dave Casper



Randy Pierson

Gran Prix International

(320) 356-9068 (Minnesota)


Webmaster's (Mark C.) Note:  Well, I sure got lucky on this one being able to ride the coattails of my brother Dave which gave me the opportunity to meet and learn more about Randy P.  While RP visited here - along with many subsequent phone calls - I was extremely impressed with his knowledge and engine work.  I would like to add my recommendation to Dave's that anyone who is looking for a hi-performance engine, having work done, or needing rigging done should place Randy at the top of his list and give him a call!.