1989 Johnson 175 GT Rebuild Thread

[Skylar.Hale]

Greetings!
My name is Skylar Hale and I am from Okie Marine located in Newalla, Oklahoma. We have recently acquired a Stratos Bass Boat with a 120hp V4 Johnson on the back and decided to swap the motor with a 175hp GT Johnson we found on Facebook market place. We gave $130.00 for the complete power head and lower with a title. The motor was complete minus the fuel pump / VRO pump. After mating the boat and motor we started with the basics.... Checking for fuel, spark, compression, and air. We found this motor was weak on compression on holes 2 & 6. We suspected the VRO pump missing had a cause in this. (VRO stopped working and starved the cylinders for oil.)

I will be posting daily of our findings and collaborating with you all on this forum as we rebuild this motor! I am extremely open to constructive criticism and will answer any questions where I can! I will upload pictures in the morning as soon as I get back to work on it!

YES WE ARE DELETING THE VRO! We will be running a 50:1 mixture directly in the fuel tank.

 

[Faztbullet]

We suspected the VRO pump missing had a cause in this. (VRO stopped working and starved the cylinders for oil.)

A VRO cannot cause certain cylinders to fail as the mixture out to carb is same for all cylinders. One of the biggest misunderstandings for VRO. Is it a flat back or bubbleback?

 

[havoc_squad]

A VRO cannot cause certain cylinders to fail as the mixture out to carb is same for all cylinders. One of the biggest misunderstandings for VRO. Is it a flat back or bubbleback?

I don't think there is any crossflow flatbacks with VRO that are 175 hp. Aren't crossflow flatbacks with VRO only 150 hp?

 

[racerone]

A GT 175 should be a bubble back.-----With big bore pistons.----A GT 175 is different.-----Have one myself for parts / rebuild.----Also has to do with propshaft rating / marketing.-----They did have to get rid of many parts in the warehouse in those years too.

 

[dwco5051]

What were you compression numbers? My 1990 175GT all were in the low 90's right after the rebuild when I bought it.

 

[Faztbullet]

Yes the 89 should be the 2.6L bubble back, but someone could have swapped powerheads,,reason I asked. The 2.6 was thin walled and many bit the dust due to overheating.