I was looking to trade my 200 SHO in on a used F300. I sent it FedEx and had it back on my boat in 3 days beginning to end. the thing comes off with four 10mm bolts in 2 mins. but I do like mid range fuel efficiency and being able to open it up for separation after a no wake zone or something like that would be nice. I don't like to run wide open and very seldom do. Bottom line is it needs a bigger prop and that will help fuel efficiency and top end speed even more. Sunday, it spun the same prop to the 6200 rev limiter and had more left. The last thing I want to add is that the very efficient Solas 4 blade prop I have been using could only be spun at 5200 rpm by the stock 200 ECU. The engine now has enough power to trim the bow up and it rides on the back 1/3 to 1/2 of the toons like it should when you are running. In addition the modded motors burn less fuel as the cruise speed is substantially higher than stock. No issues at all with longevity or reliability. I was passing bow riders on the last 2-3 miles to the ramp. Yes I currently have 2 motors modified with Hydrotec parts, built 90>115 1987 on Hoog 16'8' and still in service, built 25>35 2006 currently on 17'6' Spear Glade X, run it 3-4 days per week. my top speed increased from 32-33mph with no Bimini. PLUS my new Bimini was up the whole time and it wasn't before. My fuel efficiency went from 1.8 to 2.55 with the same prop, same RPM and this was straight into what I estimate was a 2 mph current. I filled the tank when I got there and did the math over lunch. I took my boat out Sunday afternoon to Pickwick Lake on the TN River System and put in mid lake and ran south (up river) for 35 miles without stopping. my cruise mpg was a terrible 1.8 at approx 20mph around 4000 rpm. The 200 just didn't have enough umph to get the front of the toons completely out of the water so there was drag. With clean toons, top down medium load and good prop, I was only getting 32-33 MPH. I have a 200 SHO on a HEAVY R25 with ESP. You have as much chance of blowing the power head on your 200 SHO with the remapped ECU as the guy who BOUGHT the F300.Īnyway, I am here to testify in no uncertain terms that it works and the results are just unbelievable. you boat is only rated for a 200 but Yamaha doesn't want to make separate internal combustion engine parts for 5 different HP models so they throttle the 4.2L engine with the ECU and decal for the various models. The ECU is restricted on the lower HP to fit various applications. They are identical 4.2 L 6 cylinders engines. What I found out is the Yamaha 200SHO, 225SHO, 250 SHO (Japan has a 275 SHO) and the F300 are all the same powerhead. The 2 primary concerns people have are 1) does it work? and 2) if it DOES, will the increase HP damage my engine? I got mine back a couple of weeks ago and installed it in less than 5 mins. I know this has been talked about on many sites and I have done hours of research online and on the phone. I have to share my experience with the Nizpro Marine ECU Flashing or remapping.