johnson 150 same as 175 but with smaller carbs? and starflight 125 plugs?

[art25]

Hello,

Does anyone know if the 150 johnson is a carbed down version of the 175? I found a deal on a 150 and i still have the 175 that blew up that i'm replacing. Would the 175 carbs make it a 175, like some of the smaller models having interchangeable parts, or is the bore stroke ect different?


Second quick qhestion is, does anyone know the proper spark plugs for a 1972 evinrude starflight? i'll be running heavy and fast. Thank you!

 

[SparkieBoat]

Re: johnson 150 same as 175 but with smaller carbs? and starflight 125 plugs?

here is the link for your plugs. and the answer is no, a 150 and a 175 do have differences. it is best to leave the 150 carbs on the 150. If you want a 175, sell the 150 and buy a 175.

 

[emdsapmgr]

Re: johnson 150 same as 175 but with smaller carbs? and starflight 125 plugs?

You did not state the years of the two engines. Would be helpful to know in order to provide the best answer. If you have two of the older crossflow engines, you can switch the carbs from the 175 onto the 150. The carbs on the 175 have larger throats and will flow more air and fuel. That's the only significant difference between the two engines. Good for an instant increase of 25 hp. Check to make sure both carbs have the same choke systems. Some older carbs have choke butterflys, the newer ones use the primer solenoid.

 

[SparkieBoat]

Re: johnson 150 same as 175 but with smaller carbs? and starflight 125 plugs?

I thought the 175s had different heads, intake ports and exhaust ports??

 

[emdsapmgr]

Re: johnson 150 same as 175 but with smaller carbs? and starflight 125 plugs?

On a crossflow, the base 150's and small bore (early 175's) use the same part number long block. The one year exception is 1985. That year the 175 was a high port-same as the 185. The big bore 175's (starting in 1986) are significantly different. They are basically detuned 235's. Porting was different on the 200, 235 and those big bore 175's. In order to know exactly what Art25 has in mind, it's best to know the model years of his two engines.

 

[SparkieBoat]

Re: johnson 150 same as 175 but with smaller carbs? and starflight 125 plugs?

ok..that is some great info. thanks