Looking for some advise. I have 1997 Johnson 35hp 2 stroke 3 cylinder that is sitting at 180 psi compression. It will turn 6700 - 6800 RPM's. It's been tuned to run on 100 LL avgas mixing amsoil...
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Looking for some advise. I have 1997 Johnson 35hp 2 stroke 3 cylinder that is sitting at 180 psi compression. It will turn 6700 - 6800 RPM's. It's been tuned to run on 100 LL avgas mixing amsoil...
What kind of compression can these little Mirage 35hp 3 cylinders handle? Can they handle 170? I'm going to have the head cut/milled on mine to increase compression as I hear they respond well to...
Powerabout,
I don't think so. I did talk with CDI tech (Clark). He said something about "cut the orange wire and the orange wire with a black strip on it and replace the feed to the orange wire...
Has anyone figured out how to get around the rev limiter (set at 6200 RPM) on these little 1996-2002 25/35 3 cylinder 2 stroke mirage motors. CDI does not make an aftermarket power pack with a rev....
Arltralite111, How is your 35 triple build coming along? I have one, interested to see what you have learned and did for performance.
Arltralite111, If you are looking for a 35hp powerhead, you might give Tom Booth a call at Riverside Marine in Little Rock Arkansas. The location may not be feasible for you. That's where I got my...
14apache,
No we didn't stuff the crankcase. Maybe later. Pretty happy with it.
14apache,
Runs strong. 39-40 mph on the 1548 flat bottom. Happy with it. Gets there quick also. A lot of low end torque in that little thing, comes out of the hole hard.
Thanks champ20B, Probably not going to mess with it until spring time. Time to use it right now. It's running strong.
Did a compression check, all 3 cylinders are right at 135psi. May have to shave a few thousandths off the head. Shoot for 145 - 150psi??????? Those little engines handle that? 15psi worth it?
Ok, first round of results from my little OMC 3 banger Mirage 25 to 35 conversion after a proper break in. Again this is mounted on a 1548 semi V aluminum duck boat. I'm turning 6500+ RPM's (hitting...
14apache,
Not yet. Been busy with kids: LL football, gymnastics, etc. they are running me to death. Also, taking advantage of fixing a few little other things on the boat while we are at it. Been...
Anyone on this thread have any recent updates on their quest to convert their OMC mirage 3 banger 25 to a 35? I took the easy way out. I bought a remanned 35hp power head, bored .030" over, cleaned...
So no big gains with readjusting the port timing? My machinist said he had reservations about doing that anyway (he was questioning if it would even be noticeable), even if we got the port maps of a...
Anyone know how I could acquire a port maps for my OMC 1997 25hp 2 stoke 3 cylinder? As Mr. Norstrom mentioned a few threads above "Increasing the bore size of a 25 and readjusting port timing makes...
Mr. Nerstrom, Thank you for posting and sharing your information and expertise regarding this Mirage 3-cylinder. I'm not exactly sure of all the engines you designed at OMC, but you knocked it out...
5610756108
Picks of my little 1997 25hp OMC 3 banger! Hope this works!
FastJeff57, check that .060" over a 35hp above. It was actually .030" over a 35hp bore. Just used standard OMC part number piston.
FastJeff57, We bored my 25hp to .060" over a stock 35hp. Same as 14Apache did.
All good points’ and information guys. I think I’ll leave well enough alone (cheaper too), guess “I want my cake and...
What next?????????? I also have a OMC 1996 25hp 3 cylinder. I was wanting to convert my 25hp to a 35hp, (we have 25hp restriction on our WMA's) that way I have a 35hp on a short shaft lower unit. I...
Yeah, I'm going to get after it again after hunting season is over. Should be able to get a couple mph with a few more tweaks.
Tim,
Got it. Im at 6200 WOT right now with mine GPS'ing at 37.5 - 38.0 MPH. Thats with a 14P SS powertech prop. I'm not quite to my magical mark of 40 mph, getting close.
Tim,
Thought those optical ignition systems were limited at 6200 on these engines?
Shane
Eric,
About 325lbs.
Shorai Lithium Iron Phosphate battery is the ultimate in weight versus power technology. This battery weighs in at only 4.96 pounds and offers an incredible 540 C.C.A. This is a drop in replacement...
Thanks, I thought there had to be more to a 25hp to 35hp conversion than larger pistons, larger jets and a couple degrees of timing. Thanks 14apache for the info. Any other notible differences...
I tried CDI for my '97 johnson 25 hp 3 cyl., they didn't offer anything for that power pack, regardig no rev. limiter!
14apache, Did you perform a 25 to 35 conversion on your motor? I have the same 25hp johnson motor and have converted it from a 25 to a 35, I also put boyseen reeds in. I would like to know what all...
Does anyone know what the technical difference/s was between the 1996- 2001 model 25hp and 35hp 2 stroke 3 cyl. Johnson/Evinrude cylinder head? 25hp part number shows 0339167 (obsolete/no longer...
OK, so I converted my little Johnson 1996 25hp 2 stroke 3 cylinder to a 35 HP this past year. As part of the conversion we put 35 HP jets in the carbs., went from the stock 25 HP low speed jet #31...
Thanks Mark, Good info! What is your definition of "crazy RPM's". I am currently hitting my rev. limiter at 6200R's, hence why I'm going up to a 14 pitch from a 13 pitch. Also, I am sending yo a PM!
Going try a 14P OMC first see where that puts me and go from there. I already have it raised off the transom 1 1/2" and have went back to 50:1 ratio. I saw no difference (performance wise) from...
Agree, and for what I use it for it is perfect (the beefy lower unit). I'll keep you posted as I experiment with the prop to try and reach that 35mph number!
Thanks JohnsonM50,
Going to go up to a 14p SS after duck season is over and see where that puts me. Weight distribution is good. I moved the 6 gallon fuel tank to the front, and have a Shorai...
I need to put a jackplate on my duck boat for a "smaller" outboard. Need to mount a 35hp 2 stroke 3 cyl Johnson to it (151 lbs). Boat is a 1548 aluminum modified "V" flat bottom. Any words of...
OK, got the air (or lack of) thing worked out (opened up the air box). I took the boat out this evening with a GPS and my tiny tach, here are the results. 13 pitch, stainless stock OMC prop, 6300 RPM...
Tim,
Sweet! This is just like my 1996 OMC triple. As stated in the opening comments of this thread, mine was originally the 25hp short shaft version. As you know, they made this little triple...
Just checked the plugs I pulled out yesterday and they are brown in color.
We replaced the 25 hp jets with 35 hp jets.
Fuelblndr,
I put a new set in after the break in of 25:1 fuel. Is that what you meant by check the plugs?
Yeap your right! Those too! Hunted out of a boat last year (1648 War Eagle) with a 2 stroke 3 cyl Yami mod'd out. Fast!!
Question, I am brand new to the forum so I hope someone may be able to help out. I have a 1996 25hp 2 stroke 3 cylinder Johnson that I converted to as 35HP this winter. They made this exact same...