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97 mariner 75 hp jets

bigdogjs

New member
can anyone tell me if it is possable to increase a 75 hp 2 stroke to 90 hp by changing the carb jets the manual showes the same carb but larger jets ?
 
can anyone tell me if it is possable to increase a 75 hp 2 stroke to 90 hp by changing the carb jets the manual showes the same carb but larger jets ?
Probably not. You would need both manuals to compare all the parts. The intake could be different, could be a different exhaust tuner. The timing could also be different you need to check.all parts.
 
Probably not. You would need both manuals to compare all the parts. The intake could be different, could be a different exhaust tuner. The timing could also be different you need to check.all parts.
I did check the specifications for the 75 and 90 timing is the same . I.dont know what the exhaust tuner is ?
 
That will merely cause it to run rich as all hell.

I suspect the reeds open more for the added power--it's that way on the smaller motors.

Jeff
 
The only thing you will get with 90 HP jets is a rich running engine that may even run worse. Even though the engines are identical in every way, one fundamental difference is the larger intake and exhaust ports on the 90. That's how they make more HP. So unless you plan to strip the block and put in a milling machine to open the ports up, stop now and save your money.
 
The difference is the carbs and exhaust tube. The carbs have a bigger venturi .... Jets will not improve anything.
 
Replacement power heads are the same . I think the carbs are the same they have same numbers except the jet size 75 .052/.054 90 .062/.064
Im thinking the larger jets will increase the top end max rpm from 5250 to 5500 which should increase speed
 
The carbs are not the same part number ..the 75 is a A30 and the 90 is a T90...they are different so don't waste your $$ on jets.
 
My manual shows wme 59 for 75 and wme 49 for 90 I had a buddy at carb shop measure Venturis ,are the same may be something inside is different. I know that some 2 stroke carbs can be changed for more hp like mikuni carbs . Im not looking for an argument just trying to get as much info as possible so if anyone did this successfully please tell what you did thanks
 
No as I said I'm trying to get all the information I can but it seems like you are hostile so please let it go and let's see if someone has done this before and what they did
 
No as I said I'm trying to get all the information I can but it seems like you are hostile so please let it go and let's see if someone has done this before and what they did
Not hostile you have been told many times why that wont work and you have an answer. The jets are not that expensive so buy them and try it. I am curious about why you cant be the first one to do it. then come back and start a thread on the results.
 
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Amen , amen-------It has been suggested it will not work.-----It has been suggested to buy the jets and test run since you doubt the advice posted here.--------So buy the jets .----Test run.-----You will then be an expert on the matter.
 
again if you havent done this then SHUT UP! Im not interested in your opinions just fact! so let it go Ill wait to hear from someone that tryed or was able to do it .
 
again if you havent done this then SHUT UP! Im not interested in your opinions just fact! so let it go Ill wait to hear from someone that tryed or was able to do it .
You dont need to be Einstein to figure out you will not get 15 hp from Carb jets. Get off of the recliner and put down the cheetos and go to the dealer and get the jets. Once you put the jets you will have all the facts you need. Otherwise stop wasting peoples time. Go to screamandfly.com maybe somebody there has done it.
 
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Good luck with your motor. I am sure with your extensive knowledge it will have a nice short life. By the way you dont spell tryed that way. It is spelled tried.
 
Let me apologize, bigdog, perhaps some here, including myself, can be supercilious. You could possibly gain some power with just jetting and prop here. This motor would be a good candidate to give it a try, very similar to my 115.
 
let me apologize, bigdog, perhaps some here, including myself, can be supercilious. You could possibly gain some power with just jetting and prop here. This motor would be a good candidate to give it a try, very similar to my 115.
timguy is not apologizing for me.
 
Flyingscott as for knowledge I'm a 61 year old heavy duty truck mechanic and have worked on bigger more complicated engines then most people I've had over 40 years experience rebuilding diesel and gas engines . so take your spell check and stick it , every forum has a a****** like you

Timguy thanks, still doing research I will post what I find out
 
Flyingscott as for knowledge I'm a 61 year old heavy duty truck mechanic and have worked on bigger more complicated engines then most people I've had over 40 years experience rebuilding diesel and gas engines . so take your spell check and stick it , every forum has a a****** like you

Timguy thanks, still doing research I will post what I find out
Thank you for the kind words. I dont have time to blow smoke up your a##. All that experience and you have no answer for yourself. All that experience on complicated engines and a simple two stk is kicking your a##!!! You got your answer and did not want to hear it.
 
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Big dog, Mr. Scott and I have had a few run ins over the years and I still consider him a wise mechanic. Racer can flex his muscles too, we are all human. The objective here is to exchange information with respect and modesty. What launched things off here was your continued inquiry after our techs advised and you questioned.....in itself is fine, in fact I enjoy that. Finally Mr. Scott snapped a bit, calling you a "know it all". His bad, but wait.....I think he has always been this way and we accept it, don't think much of it. You and I are similar age and also heavy equipment/marine mechanics. Sometimes these simple little 2 strokes can kick your a**. But I have gained nearly 5 hp with a jet change....and prop, with a 25/30 Johnson. It is not unrealistic to think that your Merc/Mariner cannot add 10 or 15 hp assuming that the 75 is simply a "detuned" 90.
 
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