Finally made it to the lake today. Heres the set-up. '92 Pulse 170, 94 blackmax 135 w/ premix 50:1 and 25deg total advance(no more bs ignition boxes or oil injection crap). No jackplate. Prop centerline 6 inches below pad. Mich. wheel 21p prop. With 550lbs of people/gear and nearly 30 gallons of gas and a badly to the right trim tab we tickled 54 mph gps at about 5600rpm. Im guessing theres a whole lot left in her...Im planning on getting a CMC manual jackplate with 6 in. set back. Is there any prob with one of these on this hull? Also, how high up should I be able to run the motor without pressure issues? Im also going to get a decent prop. Jw had good luck with a 23 Laser II on this boat in the current configuration. BTW, JW I cant remember if you said you tried a Tempest. Would a 23 Tempest work better if the motor is out of the water more? Im concerned a little about cavitation with the smaller Laser prop. But hopefully a 23 Tempest wouldnt bog her down if I get the motor up?? Thanks, Bryan
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Pulse 170 baseline...lets let her go faster!
- Thread starter bcrector
- Start date
ckmate225
Active member
I think 54 was a pretty respectable # for a 135. I have a pulse 186 with a 225 no setback or jack plate with the 21p prop I could get 60.0 gps, I had no idea of what kind of prop it was there were no marking on it but it had no bow lift. I just ran a 23p laser 2 yesterday, That woke that boat up tremendously. I didn't have the GPS on me but I could feel the boat lift from the water and chine walk slightly with minimal trim, I would guess at at 6000 rpm I gained some considerable speed, maybe 6-8 mph, over the other prop, I will post some numbers as soon as I can get back out.
I also have a 4 blade yamaha 24p I am going to test as soon as I get the hardware for it. I hope to see 70 this year.
I also have a 4 blade yamaha 24p I am going to test as soon as I get the hardware for it. I hope to see 70 this year.
ndaniels
Well-known member
I agree those are great #s with your current setup... you're on the right track with a jackplate for more speed and prop testing- I'd try a laser before the tempest, it's better suited to smaller power and has good bow lift... I don't think that you'll have much cavitation at all when planing (I didn't when I was running one on an 8" plate). The 23 pitch might be on the tall side, even with the plate- I'd try a 21 laserII and go from there.
Glad you got her out!!! 
Good mods you did too, but at 25 degrees fixed make sure you run at least 91 octane to be safe! That's what my merc manual calls for anyway.
As far as losing prop bite, when I had my '92 Pulse 171/Merc XR6 and a 6" setback jack plate, I never ran out of prop bite before I ran out of water pressure. And that motor had the Torquemaster LU, which had only the lower 4 holes, not the full stack of holes your FleetMaster LU has. In other words, the 26" Laser II still had good bite with the propshaft 2" below the pad! Add some intake scoops, and block off the top few holes in your LU, and you'll have the best setup for jacking the motor high.
A jackplate will help, but not NEARLY as much as a factory bow-cover. Get a bow cover on that, and you'll gain mph faster than any other mod at this point short of mounting a bigger engine. When I added the 6" jack plate to my Pulse 171, I gained about 1 mph. That boat really wants MORE setback, but you'll need to replace the steering.
I ran the 23" Laser II on that boat and hit 57 mph GPS without a bow cover, and there was still plenty of RPM's.
Here's what I'd do first: Try to find a 25" Laser II, 10" jack plate, and a bow cover. You'll have the fastest 135 2.0 around
EDIT: Also, I should let you know the 17' boats are a handlful when they 'pop' out of the water at around 58 mph. You'll need to steer the wheel about 160 degrees counter-clockwise to keep going straight! The BEST BEST mod you can do to any boat that runs over 55 mph is to replace the worn soft rubber engine mounts with solid mounts. The good news is any mods you do to this setup will work on the 2.5 liter 200 horse EFI motor you'll be buying to replace the 2.0 liter 135
Good mods you did too, but at 25 degrees fixed make sure you run at least 91 octane to be safe! That's what my merc manual calls for anyway. As far as losing prop bite, when I had my '92 Pulse 171/Merc XR6 and a 6" setback jack plate, I never ran out of prop bite before I ran out of water pressure. And that motor had the Torquemaster LU, which had only the lower 4 holes, not the full stack of holes your FleetMaster LU has. In other words, the 26" Laser II still had good bite with the propshaft 2" below the pad! Add some intake scoops, and block off the top few holes in your LU, and you'll have the best setup for jacking the motor high.
A jackplate will help, but not NEARLY as much as a factory bow-cover. Get a bow cover on that, and you'll gain mph faster than any other mod at this point short of mounting a bigger engine. When I added the 6" jack plate to my Pulse 171, I gained about 1 mph. That boat really wants MORE setback, but you'll need to replace the steering.
I ran the 23" Laser II on that boat and hit 57 mph GPS without a bow cover, and there was still plenty of RPM's.
Here's what I'd do first: Try to find a 25" Laser II, 10" jack plate, and a bow cover. You'll have the fastest 135 2.0 around
EDIT: Also, I should let you know the 17' boats are a handlful when they 'pop' out of the water at around 58 mph. You'll need to steer the wheel about 160 degrees counter-clockwise to keep going straight! The BEST BEST mod you can do to any boat that runs over 55 mph is to replace the worn soft rubber engine mounts with solid mounts. The good news is any mods you do to this setup will work on the 2.5 liter 200 horse EFI motor you'll be buying to replace the 2.0 liter 135
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Thanks for the feedback thus far. I was thinking a 6 inch jackplate would be good for more than just 1 mph. Maybe Im being a little over-protective of the boat but I probably wouldnt be able to stop thinking about the transom craking with more than the minimal offset (the basic idea was to get a jackplate mainly to ease the adjusting of engine height) I like the bow cover suggestion but am willing to give up the mph to move about the front of the boat (I love BR's!). After considering it a little more, maybe I should just toy with raising the motor with no jackplate and get a Laser prop. Would I be able to take it much higher than 6 inches without any offset or LU mods? Would it be worth the effort or would the gains be minimal from say 6 inches to 3 inches below the pad? About the timming, it gets a steady diet of 93 octane...I was thinking I could put a few more degrees in it given that the compression is low but will probably leave it. About the mounts, as I was letting the others take her around, I did notice the cowling moving around a fair amount in relation to the rock steady mid section. Thats something im going to look into as well
ndaniels
Well-known member
If you're gonna pull the motor to raise it, might as well add a jackplate, imo. You'll have to be sealing the mount holes over and over as you play with engine heights. The manual plates arn't that expensive and will allow you flexability with engine heights for running fast, or heavily loaded, watersports, ect.
Also the water scoops are well worth the money as is a waterpressure gauge (if you don't already have one). Scoops are easy to install, too.
Also the water scoops are well worth the money as is a waterpressure gauge (if you don't already have one). Scoops are easy to install, too.
I second that. Add a CMC or RapidJack or other manual jack plate so you can play with engine heights easier, just don't expect much gain if that's all you do. Do the water scoops for higher heights. The bow cover is the best, you can snap that on for speed runs then roll it up and store for full-boat use. A bow cover helped my Pulsare gain 6 mph
The very easiest way to gain speed and hole-shot is to do nothing else but pull that nice 135 2.0 and install a 2.5 200............................
The very easiest way to gain speed and hole-shot is to do nothing else but pull that nice 135 2.0 and install a 2.5 200............................
Update: I ended up buying a new Laser II 23p prop, CMC 5.5 manual jackplate, and water intake scoops as well as a trim guage. This gave me the chance to replace the old engine mounting bolts and washers with new bolts and nice big aluminum backing plates and copious amounts of silicone. The first time out with the goodies had the same ~550lb plus 30 gal load but with with rough water (too rough really) However, I stayed in it to 56mph GPS before I had to let out due to some items wanting to fly out of the boat. It felt pretty strong. It seemed that I was able to air out the boat with adding some trim and seemed it had more in it....it started to smooth out before I let out of it. The prop centerline was at about 4.75 in below the pad. If I remember right, I had it up close to 1/2 trim at times. The next test was on a smaller calmer lake with the prop centerline at about 3.5 below the pad. There was no change in water pressure (over 20 psi WOT). However, this time out, anyhing much over 1/4 trim and the prop would start to blow out... at times kicking to the right suddenly. It seemed I couldnt get the bow up much at all by adding trim but there really wasnt any roost...it seemed that more of a roost was kicked up (although small compared to some of you guys) when the motor was deeper. The boat felt a little lazy although the rpms were up around 5700 with it set at 3.5in. I wasnt able to get more than 56mph out of her. The air was warmer though. Is it possible to have the motor too high even if rpms are under 6k and pressure is good? I've read on S&F that Laser props "turn into boat anchors" if they are surfaced and that they are meant to be buried on stern drives etc. I would think that this would be true on a heavy boat....I'm not sure that a Pulse 170 would be considered heavy but maybe so. What do ya think...set er down to 5 below the pad and let 'er eat?
ckmate225
Active member
I think you are at the point now that you should start testing some different props and engine hight combinations. I am running a 23p laser 2 real deep and get a lot of bow lift but it is 6.5" down. With my 2.4 225 I am getting just about 64 mph gps @ 6000 rpm. I also have read the laser will drop the bow if its too high. I think you are on the right track with that setup.
I still think you are seeing fantastic # with the 135hp.
As far as the boat weight goes..The pulse is a little heavy for its size compared to a hydrostream or an allison.But its a solid boat that will take what ever you throw at it, you just can't expect to see same performance that you would with a super light hull.
Keep testing and post your results.
I still think you are seeing fantastic # with the 135hp.
As far as the boat weight goes..The pulse is a little heavy for its size compared to a hydrostream or an allison.But its a solid boat that will take what ever you throw at it, you just can't expect to see same performance that you would with a super light hull.
Keep testing and post your results.
The back end will walk sideways when you 'break-over' into the high 50's when the boat 'pops' onto the pad. I've had a LOT of experience driving thru this when I had my Pulse 171 with the XR6 150 and the 26" Laser II prop. I experienced this once with your boat when I was out of gas, by myself, and had my 23" Laser II on the motor. Congrats, you've been on the pad! 
When the boat pops onto the pad and the back end slides over a foot or so, you have to immediately counter-steer about 120 degrees of steering wheel rotation. When you slow back down and pass thru this zone, you'll swing the wheel back around 120 degrees to the original 'below 56 mph' angle. Practice, practice, practice...........
The BEST way to get rid of most of this sliding around is to replace the engine mounts (4) with solid mounts. The rubber mounted standard 'fishing' motors all have soft rubber mounts for comfort, but they really move around when the boat pops onto plane and change the prop loading. This is what you're actually experiencing, a change to the prop loading on the engine.
When the boat pops onto the pad and the back end slides over a foot or so, you have to immediately counter-steer about 120 degrees of steering wheel rotation. When you slow back down and pass thru this zone, you'll swing the wheel back around 120 degrees to the original 'below 56 mph' angle. Practice, practice, practice...........
The BEST way to get rid of most of this sliding around is to replace the engine mounts (4) with solid mounts. The rubber mounted standard 'fishing' motors all have soft rubber mounts for comfort, but they really move around when the boat pops onto plane and change the prop loading. This is what you're actually experiencing, a change to the prop loading on the engine.