Information needed

[johnson25hp]

Hi, new guy here. I have a 1998 model 25 hp Johnson. It is on a pontoon boat, so I believe it is a long shaft. My question are as follows:<br /><br />1. What is the proper fuel/oil ratio?<br /><br />2. Where can I get a repair manual for this year?<br /><br />3. I have heard that there is only bolt-on differences between the 30 and 25 hp models. Is this true? If so, what are the differences?<br /><br />4. How can I increase the horsepower?<br /><br />Sorry for such a lengthy first post. Any help is greatly appreciated as the search function yielded no answers.

 

[JB]

Re: Information needed

Too many questions at once, Johnson.<br /><br />Your ratio is 50:1, <br /><br />You can gat a manual at the top of the page.<br /><br />No, there are more differences.<br /><br />Don't bother to try. If you want more horses buy them.<br /><br />Good luck.

 

[johnson25hp]

Re: Information needed

Thanks for the info. I know asking how to increase hp on a 25 hp motor is strange, but our local lake regulations are ridiculous and only allow 25 hp. If you would, please elaborate on what exactly the differences are since Johnson's website lists the same bore, stroke, and displacement for the 25 and 30 hp models. I'm not questioning your knowledge, just curious and anxious to learn.

 

[Hooty]

Re: Information needed

That's a real tough question to answer Johnson.<br />It could be something as simple as a restrictor plate, different jets or timing. Could be more complicated like changing carb(s), pistons, reads, etc. or it just might be nearly impossible. Unless someone with knowledge of that particular engine comes along with a sure-fire answer, I'd forget about.<br /><br />c/6<br /><br />Hooty

 

[steelespike]

Re: Information needed

Johnson,<br />Dont bother,even if it was a 25 dollar bolt on conversion. On a pontoon boat it probably wouldnt<br />give you 1/2 a mph. Pontoons are great for the things they are biult for but speed is not one of them.If you trippled your horsepower it would only give you 8 or 9 miles per hour.At a tremendous cost in gas.But just think of all the things you could do with a pontoon. I was thinking of putting a porch glider on mine.<br /> Happy boating.