Engine swap: 50hp to 150hp

[wimico]

I have a 24' pontoon with a '85 50hp #A131285 and I have aquired an '84 Black Max 150hp #6568407. I am considering swapping the 50 for the 150 and aside from beefing up the transom I want to know if the controls for the 50 will work on the 150. I have all the controls for the 150 but it would require much more metal fabrication and re-routing of cables as the 150 controls are made to mount exactly opposite of the existing controls. My machine shop buddy says beefing up the transom would be no problem (along with the other fabrication). The boat is rated for up to the 150 but I just don't trust the strength of the existing transom.
Does anyone see any major "gotchas" in doing the swap and using the existing controls?

 

[Superjetjim]

Re: Engine swap: 50hp to 150hp

I would expect the control boxes to be compatible (same pin out at the exit of the control box plug?) check your steering is sound and up to the job - 150 is about the limit for cable steer if that's what youve got?

 

[wimico]

Re: Engine swap: 50hp to 150hp

I do have cable steering. I know that the 150 is really more than I need but I got a good deal on it and it seems to be in good shape. It starts and runs great on my motor stand. If I do this I don't intend to make my pontoon a screamer at wot all the time but the 50 is a little short when trying to pull a tube or get back to the dock with a thunderstorm approaching.
Thanks for the response. Any other thoughts on this swap will be greatly appreciated.

 

[Faztbullet]

Re: Engine swap: 50hp to 150hp

The only problem with controls will be if the 50 did not have trim you will need to run wires for it. Other than that it should be plug and play

 

[wimico]

Re: Engine swap: 50hp to 150hp

The 50 does not have trim and I know I will have to run the wires and mount a trim switch in my console. I will also have to mount the pump under one of my rear seats.
As soon as I get my camera batteries charged I am going to attach photos of my existing controls.
My existing controls have the cold start built into the shift/throttle arm. Pull out the shift arm and push forward for cold start which throttles up in neutral. I trust that will work as well? The 150 controls have a separate cold start lever that lifts up.
Thanks

 

[Superjetjim]

Re: Engine swap: 50hp to 150hp

The 50 does not have trim and I know I will have to run the wires and mount a trim switch in my console. I will also have to mount the pump under one of my rear seats.
As soon as I get my camera batteries charged I am going to attach photos of my existing controls.
My existing controls have the cold start built into the shift/throttle arm. Pull out the shift arm and push forward for cold start which throttles up in neutral. I trust that will work as well? The 150 controls have a separate cold start lever that lifts up.
Thanks

Yes it should work fine - both achieve the same thing (minor throttle advance) but using 2 x different mechanisms in the control box to achieve it. Ultimately they both pull the throttle rod a short distance.

I changed from the blue/silver Merc control box (81 era) to the newer (early 90's era) with the changes you mention (cold start) with no issues.

Jim

 

[wimico]

Re: Engine swap: 50hp to 150hp

As you can see from the photos, the original controls configuration will be a much cleaner job than trying to change to the Quicksilver controls.



I was mistaken about the separate cold start lever on the Qucksilver.

 

[SparkieBoat]

Re: Engine swap: 50hp to 150hp

I would sell that 150 and get a good 115 or even a 70 for a 24' pontoon ..you will not get hardly any more speed with the 150 but it will drink 2x the fuel. if you use the 150 make sure you prop it right

 

[wimico]

Re: Engine swap: 50hp to 150hp

I would sell that 150 and get a good 115 or even a 70 for a 24' pontoon ..you will not get hardly any more speed with the 150 but it will drink 2x the fuel. if you use the 150 make sure you prop it right

Know anyone that wants to trade a good 115 for a 150?