Removing Foam

[flatheadsteve]

In my experience with this boat it has been the opposite. The higher I can run the motor without cavitation, the faster it goes. Assuming I'm in open water and just going from A to B, I like to find that line where the prop is just about to blow out. That's where I get the most speed. As little drag in the water from lower unit as possible.

I'm sure your right I've never run a jack plate on anything but the xpress I have now and its the pad hull at speed I think the lower unit is all thats in the water.

 

[YeOldeRusty]

I'm sure your right I've never run a jack plate on anything but the xpress I have now and its the pad hull at speed I think the lower unit is all thats in the water.

Not sure how your boat is setup, but typically if you add more setback you can run the motor higher. Think about the water coming off the bottom of the boat while on plane. The hull has forced it down and once it clears the rear, it's coming back up to the level of the water around it. Well, when you move the motor further back, it can be raised higher since the water is higher. If that makes any sense.

I typically measure in relation to the cav plate on the motor. Depending on the prop, I can raise my motor to where the cav plate is ~4 inches higher than the bottom of the hull.

 

[flatheadsteve]

Not sure how your boat is setup, but typically if you add more setback you can run the motor higher. Think about the water coming off the bottom of the boat while on plane. The hull has forced it down and once it clears the rear, it's coming back up to the level of the water around it. Well, when you move the motor further back, it can be raised higher since the water is higher. If that makes any sense.

I typically measure in relation to the cav plate on the motor. Depending on the prop, I can raise my motor to where the cav plate is ~4 inches higher than the bottom of the hull.

I have 10" of setback on my jack plate. I have tested it multiple ways and the dealer made it a point on the test ride to show me its sweet spot. I can run 20-30 mph with it lifted up but around 35mph the boat lifts up onto that bottom "pad" and I have to drop it another inch or 2 or it cavitates

 

[Still Afloat]

I usually notice how high other boats ride when I'm running right there with them. So I don't think its a speed thing necessarily.

I am actually happy with the speed I'm getting with how it's set up now. I really think I've squeezed all the juice I can get without A. Losing weight (my original question), or B. Adding horsepower.

OutboardEFI recently came out with their tune for the Yamaha 50-70hp. Send out your ECU and they can get the 50 and 60 up into the high 70hp range. I haven't heard anyone complain about reliability issues after having their ECUs flashed. I'm out of warranty anyway.

Sounds like fun if you are willing to spend $700 for an ECU flash. Personally I wouldn’t do it unless there is a way to backup and restore the OEM flash. I went the route of online flashing on a Camaro back in 2010 and had some issues. The car had mild mods including a cold air intake and long tube headers. I finally gave up on the on-line vendor, went to a performance shop and got a great dyno tune.

Obviously automotive and marine tuning have different complexities but, I would have been screwed if I didn’t have a way to restore the OEM programming.

Edit: Depending on the year of your 50hp, you may be able to do a DYI 70hp upgrade with a new OEM ECU. The newer F50, F60 and F70 appear at first glance to all have the same powerhead. For example; my Suzuki 9.9 was upgraded to a 20hp by replacing the ECU and baffle/spark arrestor plate. It pushes my Lowe 1448M around at ~27mph with a minimal set-up and cheap prop.

 

[YeOldeRusty]

Edit: Depending on the year of your 50hp, you may be able to do a DYI 70hp upgrade with a new OEM ECU. The newer F50, F60 and F70 appear at first glance to all have the same powerhead. For example; my Suzuki 9.9 was upgraded to a 20hp by replacing the ECU and baffle/spark arrestor plate. It pushes my Lowe 1448M around at ~27mph with a minimal set-up and cheap prop.

I would swap for a 70 ECU if they had the same valves. I think the F70 is a 16 valve, which means the ECU won't work with it. Yes, they share the same block, but having a different number of valves means the ECUs aren't interchangeable like the F50 and F60 are.

 

[FuzzyGrub]

I would swap for a 70 ECU if they had the same valves. I think the F70 is a 16 valve, which means the ECU won't work with it. Yes, they share the same block, but having a different number of valves means the ECUs aren't interchangeable like the F50 and F60 are.

The re-programmers will allude to getting the hp of the largest motor in the series, but many times there are hardware differences that go with it. The HP is not all in the ECU. Study the parts diagrams and look for differences. They will adjust for running with premium fuel, timing and fuel delivery. For me, not worth the risk.

 

[flatheadsteve]

Nizpro tunes seem fairly popular amongst the yamaha crowd. They claim some pretty steep gains on certian models. My 150sho can be bumped to 231hp....idk what I'd even done with that I've had the boat over 50mph one time. They claim 72hp from an f50 yamaha.

 

[Still Afloat]

I’m not saying that getting a tune from an online vendor is bad. It’s just good common sense to be able to revert to the OEM tune.