Pontoon Boat & Deck Boat Forum

Finally got the boat out after the Simon tune-up.

4 people. Couldn't hit more than 22 MPH @ 6,100 RPM, engine was bouncing off the Rev Limiter at 6,100 RPM.
Med throttle 20 MPH @ 5,000 RPM

Wasn't sure exactly what the alarm and stumble (rev limiter) was as analog tach was reading 5,400.

Took to shop, was missing and needed new plugs. Analog tach was off from Smart craft.

Merc techs findings. 2 people. 26 MPH at 6,100 bouncing off the Rev Limiter. Recommended larger prop.

Prior to Simonizing I'd get 29 MPH @ 6,100 RPM (analog tach +/- 200) no rev Limiter

Here's where my question is:

Currently running standard 14x13 Black Max

What would be the best bet to bring the RPMs down and speed up. Looking at a few recommended props:

Spitfire 13.4x15 - 4 blade
Black Max 13.875x14 - 3 blade
Black Max 13.75x15 3 - blade

I just do general cruising. Occasional tube towing. Want good overall performance with decent top speed. Searched a bunch of the prop topics here and it seems like they're all over the map. I don't have anywhere to borrow props, so I need to get it right the first time.

Any help?

I ran a 13 pitch spitfire on my 115 merc 4 stroke and it ran way better than my stock 15 black max. Gained a couple mph at a litte higher revs but held water so much better for trim and turns. Call Ricky at Brainerd props , he will set you up and he used to let you return for a different pitch if it didnt do what he said. But , he was always right in my case from my 250 vrod on my ranger , and my previous 3 boats .

smoker62 wrote:I ran a 13 pitch spitfire on my 115 merc 4 stroke and it ran way better than my stock 15 black max. Gained a couple mph at a litte higher revs but held water so much better for trim and turns. Call Ricky at Brainerd props , he will set you up and he used to let you return for a different pitch if it didnt do what he said. But , he was always right in my case from my 250 vrod on my ranger , and my previous 3 boats .

I checked their website. Seems they don't have any aluminum props. I'll call tomorrow and see what they might have.

He has them. I bought both my Nemesis 4 blades from him. Same as Spitfire but Quicksilver branded. Also all my stainless .

Picked up a Turning Point 13.5 x 15 4 blade prop at West Marine. Everything I've read shows this to be a suitable prop for what I have. This weekend I'll put it to the test and see what kind of numbers I get out of it.

BoatCop are you running a Mercury Smart-Craft gauge? Wondering what your GPH fuel readings are at WOT setting?

teecro wrote:BoatCop are you running a Mercury Smart-Craft gauge? Wondering what your GPH fuel readings are at WOT setting?

Yes I'm running Smartcraft. I'll let you know once I get it out.

BoatCop wrote:

teecro wrote:BoatCop are you running a Mercury Smart-Craft gauge? Wondering what your GPH fuel readings are at WOT setting?

Yes I'm running Smartcraft. I'll let you know once I get it out.

I'm still quite on the fence as to the Simonized ECU as in previous outings and contact with Simon I'm told that I must get my RPM up to see the HP improvements in force. Before being flashed my best performance on the 75 was with a 14" x 12P stainless 3-Blade other props tried were a Spitfire 13.8" x 11P and 13P also a 14" x 13P and 11P Black Max. None of these props turned over 5,500 RPM which is what Mercury calls WOT on the 75 motor. After flashing my WOT with the 14" x 12P is still 5,500 RPM and just shy of 10 GPH... So according to Simon I need to reduce pitch to gain RPM and HP so I break out the 13.8" x 11P and I'm still getting a max WOT of 5,500 RPM I'm just going slower due to decreased pitch. Try out the 14" x 13P and I'm seeing around 5K and roughly the same speed as the 14" x 12P @ 5,500 RPM... I'll contact Simon again to ask why my motor seems to have retained its 5,500 RPM limit after his flash...

Think I've learned my lesson here that small pontoons are just not meant to go much faster and 25 to 28 MPH

Prior to the Simon treatment I was pulling 29 MPH GPS at 6,200 PM with 2 on board. This was a stock Merc 90 4 Stroke, spinning a 14x13, 3 blade Black Max.

After Simon I was banging the rev limiter at 6,200 RPM, but only getting 22 MPH. It felt like there was a lot of power left on the table and my tech even found a bad spark plug.

I'm hoping the slightly smaller (1/2 inch) diameter, larger pitch (2") and the four blade will keep my RPMs up, increase speed and keep acceleration and mid-range power satisfactory. Hopefully more speed than the un-simonized 29 MPH.

I'll see what it does when I get on the River this weekend.

The prop you show in the photo is a cleaver type blade. I would highly doubt you get any benefit out of it as there's not nearly enough surface area for the "bite" you need to push a pontoon. In fact, Im somewhat amazed they claimed it was an applicable prop for a toon.

After chasing what seemed like a dragon since February I'm close to concluding that I wasted $600. I have a friend with the same pontoon, same year with a 115 merc fourstroke loaded about the same with the same prop and fuel level and his is by far better out of the hole top speed and hadling then mine.

I've tried several prop configuarations, and either I'm hitting the target rpm range with less speed or I'm hitting 29-30 MPH and 5200 rpms.

Like someone said, that 4 blade is a cleaver or surface prop. I too doubt you'll get good results. Simonizing pontoon props is a bad idea. You'll just get a bunch of prop slip which I think you're experiencing. "Cup" the Black Max and you should get better results. Good luck.

deleted - found it on the interwebs when i google Simon and ECU

slingshot wrote:Like someone said, that 4 blade is a cleaver or surface prop. I too doubt you'll get good results. Simonizing pontoon props is a bad idea. You'll just get a bunch of prop slip which I think you're experiencing. "Cup" the Black Max and you should get better results. Good luck.

Simonizing is a slang term for having the engine ECU flashed to obtain maximum horsepower. To save production costs, many engine manufacturers offer a variety of HP working off the same engine platform. eg bore, stroke, displacement, etc. For example, the Mercury 4 stroke 75, 90, and 115 and identical engines, except for the ECU. By changing timing, fuel injection and, in the larger supercharged engines like the Mercury Verado, boost pressure, they can regulate HP, without changing mechanical features.

It has nothing to do with the prop, except that a different prop may be required to take maximum advantage of the increased HP. Simon Motorsports in San Diego is one of the main companies to do this. Hence the term "Simonize".

I have been casually following the option of Simonizing, maybe because we used to play around with flashing EEPROMs many years ago, but I imagine someone has priced the actual ECU for a 115HP motor? I wonder if it's priced similarly to a Simonized flashing.