1999 Johnson 175 OceanPro Long Shaft, To Repower to Not to repower?

bobioknight

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Jun 17, 2013
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I have a 23' cuddy cabin boat (rated for a 1999 200hp size) with johnson 175hp motor, over the last couple years i have experienced some vibration at idle and know there is low compression in two of my cylinders. 4 cylinders running at 110 and 98 running in the bottom 2 (seafoam brought it up from 90). The motor starts right up, even if left sitting for months. idles good but you can see it has a slight miss. When running WOT it has a slight vibration, yet sometimes runs very smooth and other times can bogg down and gives little power, then all of a sudden run like like new (assuming new means smooth and strong)

I am in need of opinions, I do not have the ability to splurge on a $12000 repower. But I can afford either buy a rebuilt replacement or have mine rebuilt. I would prefer to spend as little as possible while making the right decision.

Should I purchase a remanufactured 175 - 200hp EFI 2 or 4 stroke motor from "OneOutboard.com"
OR Put a new powerhead on my existing carbed motor.
 

Chris1956

Supreme Mariner
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Mar 25, 2004
Messages
27,149
Re: 1999 Johnson 175 OceanPro Long Shaft, To Repower to Not to repower?

Your compression is within spec (+/1 15%). Why not tune that motor up, so it runs properly?
 

Jim311

Petty Officer 2nd Class
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May 31, 2011
Messages
169
Re: 1999 Johnson 175 OceanPro Long Shaft, To Repower to Not to repower?

If you have a miss or vibration something else is wrong but it sounds to me like you've got pretty good compression numbers so I'm not sure why you'd bother to repower when you could fix the issue for a fraction of the cost.
 

bobioknight

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Re: 1999 Johnson 175 OceanPro Long Shaft, To Repower to Not to repower?

I am just going by what my mechanic tells me. I do not know enough about these motors to make an educated decision. That is why I am here. My mechanic describes himself as a mercury guy, not a Johnson mechanic. I have not been able to find a local mechanic where I live so I am kinda stuck. I have a feeling it is a carb issue but not sure where to start, so I figured a newer motor would be easier to find a mechanic that can help. However, I am pretty mechanical so if I have a little information I am sure I can try and fix..... Any ideas would be welcome?
 

Chris1956

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Mar 25, 2004
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27,149
Re: 1999 Johnson 175 OceanPro Long Shaft, To Repower to Not to repower?

Well, purchase of an OEM Service Manual is firstest. Cleaning the carbs is nextest, followed by a water test.
 

bobioknight

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Jun 17, 2013
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Re: 1999 Johnson 175 OceanPro Long Shaft, To Repower to Not to repower?

Well, purchase of an OEM Service Manual is firstest. Cleaning the carbs is nextest, followed by a water test.

Ok, I have the original Johnson manual which illustrates tons of information including carb info...

I will start there. Any specific advice?
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,149
Re: 1999 Johnson 175 OceanPro Long Shaft, To Repower to Not to repower?

Sure, Disassemble carbs, clean them up. I don't recommend soaking plastic parts in a solvent, but blow them out with jet spray gumout. I recommend you coat them with some WD40 or something to displace the gumout solvent, after they are clean. Now install new gaskets, inspect or replace floats and inlet needles and seats.

Adjust carb mixture per specs and water test.
 
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