WOT FOR 1998 250 JOHNSON OCEANRUNNER

[HYDRASPORT84]

Can anyone tell me what the factory recommends for the WOT on this motor. I just had this motor put on my boat a 22' 1984 Hydrasport Walk Around.<br />THANKS

 

[Dhadley]

Re: WOT FOR 1998 250 JOHNSON OCEANRUNNER

Welcome!<br /><br />We target 5800 rpm with an average load. <br /><br />Good luck!

 

[HYDRASPORT84]

Re: WOT FOR 1998 250 JOHNSON OCEANRUNNER

I have only ran the boat once since the motor has been istalled. I got 5300 rpm without doing alot of trim work. The motor seemed to be turning free almost to free really.I was not comfortable pushing it any more. I just blew a 200 Merc this summer on this boat.My load was about 80 gallons of gas and 2 adults. no gear or anything. Do I need to fill the boat with fuel and try to get 5800rpm or is there a range i can stay in. Say 5300rpm to 5800rpm and still be okay. this boat is will hold 140 gallons of gas.

 

[Dhadley]

Re: WOT FOR 1998 250 JOHNSON OCEANRUNNER

Go ahead and trim it with your average load. Youll never get past the rev limiter anyway without rewiring the ignition.

 

[seahorse5]

Re: WOT FOR 1998 250 JOHNSON OCEANRUNNER

The factory redline on that motor is 6000 rpm and like Dhadley said, prop it as close to the top as you can, with a normal load. Do not prop it below 5500 rpm.

 

[HYDRASPORT84]

Re: WOT FOR 1998 250 JOHNSON OCEANRUNNER

Guys I have another issue on this WOT deal. My boat was orginally set up for a 25" motor. The Johnson is a 30". I had a professional build up my bracket for a 30" shank. The motor is mounted all the down against the bracket. Will I gain RPM's if I raise the motor up one or two bolt holes??

 

[Dhadley]

Re: WOT FOR 1998 250 JOHNSON OCEANRUNNER

The theory is that yes, you will gain rpm as you lose drag. However, how high you can mount your motor depends largely on the propeller and how it reacts to your hull design. We prefer to gain rpm with engine height rather than reducing pitch, if possible. Anytime you gain efficiency you gain performance across the board. Reducing prop bite usually gains on one end but loses on the other.<br /><br />The theory is that if the gearcase was completely hidden up and behind the hull there would be the least possible drag. Thats why surface drives are so successful.<br /><br />Try raising your motor to see what happens. You have your baseline now so make one change at a time and have fun. Tell us what the top rpm (with the average load) is now, what prop (make, design and pitch) and your accurate top speed and we can calculate the % of slip. As you make changes we can help you keep track of your progress. Dont forget to watch the water pressure.<br /><br />Good luck!

 

[HYDRASPORT84]

Re: WOT FOR 1998 250 JOHNSON OCEANRUNNER

Took the boat out for a test run today, here are the results.<br />5600 rpm wot running 39 mph<br />prop is a viper 14 3/4 x 19 pitch<br /><br />If I trimmed the motor up anymore my speed fell off. So I think these #'s are accurate.

 

[Dhadley]

Re: WOT FOR 1998 250 JOHNSON OCEANRUNNER

Thats over 30% slip. I think we can do better but thats a good baseline. We're way out of the powerband of that motor so lets raise the motor to get the r's up. That prop may start to vent as we go up but dont worry about that right now. We just want to see how the motor reacts to increased X dimension on top rpms and speed. Dont forget to note the baseline water pressure too.<br /><br />Have fun!

 

[seahorse5]

Re: WOT FOR 1998 250 JOHNSON OCEANRUNNER

If the hull is similar to the early '90s walkaround, it was very slow and completely differnt than the center console version. With an OMC 225, we barely go 40 mph out of it, if we were lucky. Your 250 should run better with a 17" prop if raising the motor doens't help.

 

[HYDRASPORT84]

Re: WOT FOR 1998 250 JOHNSON OCEANRUNNER

I do not have a psi gauge. I will just have to keep an eye on the it. This hull design is very slow, really deep vee that seems to plow through the water.This 250 handles the boat better than the 200 merc. that was previously on it though both motors top speed was about the same. The merc strugged to plane. <br /> By raising the motor will I be reducing slippage or increasing.<br />Would a 19 pitch prop with a smaller diameter help raise the rpm and still keep cruising speed in a respectable range. I would lke to cruise about 30 to 35 mph if possible, killing the motor.<br />Thanks for all the input.

 

[Dhadley]

Re: WOT FOR 1998 250 JOHNSON OCEANRUNNER

Right now we're only using about 200 hp or less of the available power. As for prop diameter, we have always had better results with larger rather than smaller. Don't spend money on a prop just yet. Lets see what happens when we get into this monsters powerband.<br /><br />If youre dieing to spend money, go get a water pressure gauge. Its the best few bucks you can spend. The whole kit is less than half the cost of one piston.<br /><br />Think about it.............

 

[HYDRASPORT84]

Re: WOT FOR 1998 250 JOHNSON OCEANRUNNER

I have not had chance to raise the motor yet. The weather has not been that great around here.<br />I have purchase a water PSI gauge though, I need some pointers on the install though, and what kind of pressure should I be getting ??<br /><br />thanks

 

[Dhadley]

Re: WOT FOR 1998 250 JOHNSON OCEANRUNNER

Make sure you follow the instructions. It has to read water pressure at the adaptor plate, not in-line from the tattle tale like a crossflow.<br /><br />Good luck!

 

[Reel Precision]

Re: WOT FOR 1998 250 JOHNSON OCEANRUNNER

Hydrasport84,<br />I had a friend who used to have the same setup w/a 200 Mercury. The boat would run about the same speed 38 0r so. Big heavy hull. I remember it was a good boat though. How do you like the 22WA?

 

[HYDRASPORT84]

Re: WOT FOR 1998 250 JOHNSON OCEANRUNNER

reel precision<br />I like the boat fine , but it is heavy and diffcult to tow, it also seems to take alot of water. I can not just follow any boat out or I will be on ground in a hurry. I have had to put it back on the trailer and go to another ramp, my friend with a 22' aquasport went out fine, my boat would hit bottom.<br /><br />dhadley<br />The gauge I purchased was an after maket so instructions are not specfic to my engine.Do you have any experience with the instulation of a psi gauge.

 

[Dhadley]

Re: WOT FOR 1998 250 JOHNSON OCEANRUNNER

Sure. Youll pick up the water pressure at the adaptor plate. Thats what the powerhead sits on. Look on the starboard side down low and youll see a couple of allen head plugs. Take either one out and screw in your fitting for the hose. Mount the gauge, run the hose, plug on the hose to the gauge and fitting. Simple.<br /><br />Good luck!

 

[HYDRASPORT84]

Re: WOT FOR 1998 250 JOHNSON OCEANRUNNER

Dhadley,<br />I installed the water PSI gauge today,but it is not working. I ran the motor in the yard at idle on the water hose but I did not get any reading on the gauge. The line is clear, I can siphon water through the hose going to the gauge. There is not any water being pumped through it.<br />HELP.

 

[Reel Precision]

Re: WOT FOR 1998 250 JOHNSON OCEANRUNNER

Hydrasport84,<br />Are you from Washington NC?

 

[HYDRASPORT84]

Re: WOT FOR 1998 250 JOHNSON OCEANRUNNER

Reel Precision <br /><br />YEA, DO YOU KNOW ME. I SEE IN YOUR PROFILE THAT YOU ARE FROM NEW BERN. THAT IS WHERE I GOT THE BOAT FROM.