10hp limit lake, evinrude 9.9 needs help catching up

[imported_aaron]

So we fish in a tournament where there is a 10hp limit, so we run an evinrude 9.9(i believe a 98) I will get the model umber tomorrow. We get absolutely smoked on the lake. There are larger boats out there than ours, and we still get smoked. I think some are running 15hp, what can we do to our 9.9 to pick up some extra hp? I cannot find any info on this anywhere!! Thanks.
AK

 

[imported_aaron]

Re: 10hp limit lake, evinrude 9.9 needs help catching up

sorry, I think its a 1998 but I will find out for sure tomorrow. Our boat is a 1986 16ft polar kraft aluminum. It has wood decking so its kind of heavy. I don't know what prop to run on this setup either. It seems as if the engine doesn't get up to a high enough rpm.

 

[samo_ott]

Re: 10hp limit lake, evinrude 9.9 needs help catching up

to change the 9.9 over to a 15hp (and illegally fish!) I believe you need to change the carb and tune the exhaust differently... at least for older models... not sure about 1998's...

 

[RPJS]

Re: 10hp limit lake, evinrude 9.9 needs help catching up

Have you checked to see if your outboard is running correctly, you may have dropped a cylinder.
Do a compression check you should get 80+psi in both cylinders and within 10% of each other. I would then run the motor and pull each plug lead, if the cylinder is firing you will hear a noticable drop in revs when you remove the lead.

 

[jaymasta]

Re: 10hp limit lake, evinrude 9.9 needs help catching up

find the biggest motor that you can fit the 9.9motor cover on and then you'll have lots more power with everyone thinking 9.9, there was a guy out here that a 15lid on a 20hp, and most 15/9.9 are the same so maybe you could get a 20 and fit your 9.9 lid on it good luck LOL

 

[imported_aaron]

Re: 10hp limit lake, evinrude 9.9 needs help catching up

Most of the guys fishing in these tournaments either work at or ar part owners of one of the local boat shops. They seem to have some tricks up their sleeves on these engines. It's rediculous how fast these boats really are! They are literally twice as fast as we are. I don't believe we are having any engine malfunctions, just need the right prop, and any extra horsepower we can acheive.

 

[xtraham]

Re: 10hp limit lake, evinrude 9.9 needs help catching up

find an old timmer that used to race them, it used to be a big past time in the sixty's I remember the talk of tilosen carbs. porting, windows in pistons, shaved heads ect. the outboards of old are im sure or differant than those of today, but i do remember they where LOUD and they sounded like bumble bee's. good luck

 

[Rancherlee]

Re: 10hp limit lake, evinrude 9.9 needs help catching up

are they running similar sized boats as you, a wood floor 16foot is ALOT to push with a 9.9/15. Maybe you could pick up a 12-14 foot bench seat boat which MIGHT plane out with a 9.9/15 for cheaper then you could convert your 9.9 to a 15hp going to a 15 from a 9.9 will only get you another 2-3mph and won't plane out your boat.

 

[imported_aaron]

Re: 10hp limit lake, evinrude 9.9 needs help catching up

THere are some boats that weigh MORE than my boat. My wood flooring is not treated, it is 5/8 plywood. Anyways there is a flat bottom 18ft john with a 7ft beam running a nissan 15hp, and he really beats us bad. He has to weigh more than our boat, he has treated plywood in his boat.

 

[iwombat]

Re: 10hp limit lake, evinrude 9.9 needs help catching up

How difficult is it to go up from a 9.9 (or a 9.5 in my case) to a 15? Simply a matter of new pistons and machining or is it an entire case swap?

 

[roscoe]

Re: 10hp limit lake, evinrude 9.9 needs help catching up

Have you tried talking to your competitors, especially the ones that work at the boat shops?

Although there is competition involved, some of these guys may be more than willing to lend you a hand, or at least check your motor over.

If speed is all that important, I would:
buy a 15 hp,
swap the entire powerhead with your 9.9 hp,
leaving the serial number and the model number of the 9.9 on the transom plate.
Also, replace the welsh plugs on the top of the motor that show the model/serial numbers.

Then buy the lightest little 14' boat you can find and put the new motor on it.

Put the old powerhead on the other motor, and mount that on your current boat.

Use the new fast boat for the tourneys, and the old slower boat for practice and when speed is not a concern.

Then go win the next tournament, knowing in your heart, that you cheated.

 

[clemsonfor]

Re: 10hp limit lake, evinrude 9.9 needs help catching up

buy you an older used 15/20 hp etc and paint the cowl up to look factory just replace the higher hp # with 9.9. It will still be a 15 or 20 hp but will look like a 9.9 from a didtance so unless they check you motor tiltle or run your serial #s they will never know.

-Nate

 

[jtexas]

Re: 10hp limit lake, evinrude 9.9 needs help catching up

How difficult is it to go up from a 9.9 (or a 9.5 in my case) to a 15? Simply a matter of new pistons and machining or is it an entire case swap?

parts catalogues here: http://epc.brp.com/login.aspx?Retur...rands=ej&lang=E&AspxAutoDetectCookieSupport=1

You could compare the two, see which parts are different.

aaron, reduce prop pitch by a couple inches (knowing that without a tach you risk overreving), get a set of trim tabs, exchange the 5/8" for 3/8" ply, replace the trolling motor battery with a smaller one, get rid of the cranking battery and use the rope, take out the seats, carry less fuel, loose 30lbs, get a smaller lighter partner, polish the bottom of the boat and the lower unit, replace texas and carolina rigs with unweighted senkos, replace the fire extenguisher with one half its size, reduce the ice requirement by getting a better-insulated cooler for the beer, only fill the livewell half-way...should I continue?

 

[iwombat]

Re: 10hp limit lake, evinrude 9.9 needs help catching up

Cylinder and crankcase - different
Cylinder head - different
Crankshaft - different
Connecting rod - different

Well, so much for that idea.

Thanks for the link though. Direct link didn't work, but going through the front door did.

 

[baconbiscut]

Re: 10hp limit lake, evinrude 9.9 needs help catching up

Alright heres what you do go to www.smalloutboards.com and scroll down the home page a little bit and you find the something that says 9.9 to 15 click on it last i checked i tnink it shoes ya how. but not sure give it a shot and see if it works

 

[imported_aaron]

Re: 10hp limit lake, evinrude 9.9 needs help catching up

Ok, well first off, I am not trying to "cheat", I am just trying to get the most out of my 9.9. I just wondered if anyone knew of any cheap tricks or mods for these motors(since they are almost exactly like the 15 I assumed there would be some). I never said I was going to go and get a 100hp motor and put 9.9 stickers on it. I just said that these other "heavy" boats are out running us, and I wanted a little extra go. The motor has been gone over by a tech a few months ago and was given a clean bill of health. THis was also on a smaller boat, so I need to know if I should change props etc.... Sorry for being unclear.

 

[ezeke]

Re: 10hp limit lake, evinrude 9.9 needs help catching up

I don't know what prop you are using, but once you have gotten the height and trim set as well as possible, you might want to try an OMC prop number 176266.

It is a four blade 10 X 9 aluminum that they advertise for "heavy load". It may not help the top end, but should give you better thrust than any of the others.

 

[Silvertip]

Re: 10hp limit lake, evinrude 9.9 needs help catching up

If you are on a 10 HP lake and others are running 15's, you can expect to get beat to the best holes. Why aren't they being disqualified? And you can also bet that those who run really fast have more than 15's under their 10 HP cowls. Just like entry level auto racing, there should be a claiming rule in amatuer tournaments. Lose your boat a time or two and that will level the field..

 

[clemsonfor]

Re: 10hp limit lake, evinrude 9.9 needs help catching up

Also this just came to mind.

What year is your motor, i have read that outboards changed hp rating standards in the mid 80's. This took them from crank rated hp to prop rated hp. If you have an early 80's or earlier 9.5 hp than it will be several hp under a newer 9.9 hp right of the bat not to mention the power that is lost due to wear and tear and lower compression. Just a thought

-Nate

 

[ezeke]

Re: 10hp limit lake, evinrude 9.9 needs help catching up

Seems to be some confusion here, I read it that Aaron's motor is a 9.9 which were made from 1974 on.

The 9.5 hasn't been made since 1973 and is a totally different motor.