Upgrade 25 to 35 '99 possible?

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strangeday

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I have a 1999 25hp Johnson 3 cylinder. Seems to me that this unit is very similar to the 35 of the same year. Is an upgrade from 25 to 35 possible?

If it is possible, what parts need to be changed and what would the approximate cost of those parts be?

Sorry if this topic has already been covered here, but I was not able to find any information using the search function.
 
wbeaton

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Re: Upgrade 25 to 35 '99 possible?

strangeday said:
I have a 1999 25hp Johnson 3 cylinder. Seems to me that this unit is very similar to the 35 of the same year. Is an upgrade from 25 to 35 possible?

If it is possible, what parts need to be changed and what would the approximate cost of those parts be?

Sorry if this topic has already been covered here, but I was not able to find any information using the search function.
Click to expand...

Go to the epc.brp.com and check out the part catalogues for both motors. 1999 is a little too new for me, but isn't the 35 hp a triple and the 25 hp a twin cyl? If so, then an upgrade is not possible.
 
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strangeday

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Re: Upgrade 25 to 35 '99 possible?

Thanks for the tip on that website. It isn't working for me at the moment, but I will check back later. It looks like a really good resource. I wonder what parts I should check? The motor is definitely a 3 cylinder, odd as it may sound. I have been going through the clymer's that I have and it looks almost identical to the 35. I am an amateur and not sure what parts would be different. I assume that it is only the fuel system that would be different. I have a photo of it and I will try to post it. The motor is the largest and heaviest 25 2 stroke I have ever seen.
 

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strangeday

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Re: Upgrade 25 to 35 '99 possible?

So I did finally manage to get on the bombardier site to look at parts. They don't have my model J25R3SSB but I took a guess at one that looked similar. It listed 2 different carbs, a 25HP and a 35. So maybe I just change the carbs? Maybe just the jets?
 
kenmyfam

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Re: Upgrade 25 to 35 '99 possible?

strangeday said:
Thanks for the tip on that website. It isn't working for me at the moment, but I will check back later. It looks like a really good resource. I wonder what parts I should check? The motor is definitely a 3 cylinder, odd as it may sound. I have been going through the clymer's that I have and it looks almost identical to the 35. I am an amateur and not sure what parts would be different. I assume that it is only the fuel system that would be different. I have a photo of it and I will try to post it. The motor is the largest and heaviest 25 2 stroke I have ever seen.
Click to expand...

Looks huge for a 25HP !!!!
 
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Ruggybuggy

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Re: Upgrade 25 to 35 '99 possible?

strangeday said:
So I did finally manage to get on the bombardier site to look at parts. They don't have my model J25R3SSB but I took a guess at one that looked similar. It listed 2 different carbs, a 25HP and a 35. So maybe I just change the carbs? Maybe just the jets?
Click to expand...

Did you ever figure this out? I have the same motor and if it were just a jet change and would be all over that!
 
tashasdaddy

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Re: Upgrade 25 to 35 '99 possible?

look at pistons, rings, exhaust, carbs and jets
 
14ftgrumman

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Re: Upgrade 25 to 35 '99 possible?

tashasdaddy beat me to it.

ylou might be able to go to a 35 carb, but check if the carb mounting gasket is the same- if not, carb and intake might have to be changed.
 
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wilde1j

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Re: Upgrade 25 to 35 '99 possible?

The 25 is a 2 cyl motor ... the 35 has 3 cylinders.
 
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stingertrey

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Re: Upgrade 25 to 35 '99 possible?

I Read some places that people Have bored the intake on the block to match the larger intake of the 35 hp carb and changed the prop on there motor to make it faster but also try to bog the motor a bit to keep it at the same rpms it was running before.. and they were picking up considerable speeds and power
 
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Re: Upgrade 25 to 35 '99 possible?

stingertrey said:
I Read some places that people Have bored the intake on the block to match the larger intake of the 35 hp carb and changed the prop on there motor to make it faster but also try to bog the motor a bit to keep it at the same rpms it was running before.. and they were picking up considerable speeds and power
Click to expand...

Intakes between 35hp and 25hp seem to be the same part number so just a carb swap should do it. I could see a re-prop.
 
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Ruggybuggy

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Re: Upgrade 25 to 35 '99 possible?

tashasdaddy said:
look at pistons, rings, exhaust, carbs and jets
Click to expand...

I just checked and the pistons and head are different but intake and ignition ignition modules seem to be the same. Wonder how the motor would run on the 35hp carbs jetted down some?
 
1946Zephyr

1946Zephyr

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Re: Upgrade 25 to 35 '99 possible?

The 35 was a 3 cylinder? Since when? I thought the newer engines reduced cylinders over the years, i.e 1959 50 hp vs. 1972 50hp and so on. Interesting that the 35 would have been offered in a 3 cylinder.:cool:
 
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Ruggybuggy

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Re: Upgrade 25 to 35 '99 possible?

1946Zephyr said:
The 35 was a 3 cylinder? Since when? I thought the newer engines reduced cylinders over the years, i.e 1959 50 hp vs. 1972 50hp and so on. Interesting that the 35 would have been offered in a 3 cylinder.:cool:
Click to expand...

The three cylinder 25hp and 35hp were made from 1996-2001.
 
1946Zephyr

1946Zephyr

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Re: Upgrade 25 to 35 '99 possible?

hmmmmm must not have been a big hit, to only be made for 5 years? Were they a good motor?:confused:
 
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Ruggybuggy

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Re: Upgrade 25 to 35 '99 possible?

1946Zephyr said:
hmmmmm must not have been a big hit, to only be made for 5 years? Were they a good motor?:confused:
Click to expand...

I just bought the boat and motor last weekend. I cleaned the boat today and decided to degrease the powerhead. I sprayed my degreaser on the rinsed with water from the hose. I wanted to start the motor right away to let it warm up and dry but it won't start. There is no spark so I'm thinking something in the stator is wet and not sending a signal to the ignition module. Hopefully the fan I set up to blow on the motor for the night will dry things out. I've done this thing before on my Yamaha and never had a problem.
 
1946Zephyr

1946Zephyr

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Re: Upgrade 25 to 35 '99 possible?

I bet with smaller pistons though those should be smooth runners. If you don't have spark, you might have to have the power pack tested.:cool:
 
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Ruggybuggy

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Re: Upgrade 25 to 35 '99 possible?

I let it dry out last night and it started this morning. I took it out on the lake today and I'm impressed. The idle does have the typical 2 stoke idle but once up and running it was very smooth. The motor is electric start but I tried to pull start it. This is one of the easiest pull starts I've ever used. I have a 2001 Yamaha 4 stroke 15hp and it's much harder to pull start and it's easy. The 25hp would start with one very easy pull from a sitting position.

I'm still wonder what could have gotten wet and cause the no start?
 
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