115 merc 4 stroke on crestliner superhawk 1700

[River-Runt]

Re: 115 merc 4 stroke on crestliner superhawk 1700

Gents, this is a great thread for me as I also purchased a new boat this year and am considering a prop change. Mine is an 09 Lund Pro Sport 1700 with a 2010 Merc 90hp ELPT, the prop is a Merc 13 X 19. As Wallyhead pointed out the performance of this fuel injected engine changed dramatically as I got it broken in. I had similar holeshot woes initially, and the performance improved considerably as the engine hours aproached 20. I currently experiance the blowout at higher speeds & RPM, ususally when making relatively minor course changes. With a full tank of gas and similarly equipped to your boat my son & I can get this boat to about 45 - 48 mph, on the boats speedo, and will be running 6K + RPM. I am also considering the Turning Point Hustler prop with a 19 pitch but more to alleviate the blowout issue and to help bring down the max RPMs a bit. Timdan94 have fun with your boat and post your upgrade and results, I look forward to reading them.

 

[timdan94]

Re: 115 merc 4 stroke on crestliner superhawk 1700 (update)

Re: 115 merc 4 stroke on crestliner superhawk 1700 (update)

We went out saturday and ran for a while. I went out today myself I was running the 13X17 prop I was getting 41mph at 5400-5500 rpms. It seems to be getting better holeshot wise now. Hopefully getting more hours on it will make it better and let it wind up more.

 

[River-Runt]

Re: 115 merc 4 stroke on crestliner superhawk 1700

Hi, just wanted to update you on changes I made since my last post. I went with the Turning Point Hustler 13.25 X 19 prop for my boat. Comparing it to the Quicksilver prop that was on my boat you could see that the Hustler was a much larger prop, it has more rake than the Quicksilver prop giving the blades much more surface area. Performance wise this prop eliminated the issues I was having with cavitation and seems to have improved the holeshot performance, although the jury is still out on the holeshot since I have not had the boat heavily loaded with this prop. It does lift the boat a bit on plane and seems to help keep the rpms down a bit at WOT, which is what I wanted. It may be a smidgen faster but that is pretty difficult to establish with just the boats speedometer. Overall handling with this prop is much better and it even gets it on the trailer easier, even the coffee tastes better with this prop. I think a prop upgrade, whether the Turning Point or the Solas will resolve your issues also, amd the Merc props make good spares.

 

[timdan94]

Re: 115 merc 4 stroke on crestliner superhawk 1700

Update. I've been running the boat more and have since put smart tabs on with 60lb actuators. I'm still only getting 5400-5500 rpms out of it with me and full fuel and gear. I'm debating on calling and ordering the 40lb actuators for the smart tabs. I'd like to be able to ski behind this boat but the way it is its just not going to happen. For those that say wait til I get more hours on it is there that drastic of a change in the hole shot or just a subtle change?

 

[steelespike]

Re: 115 merc 4 stroke on crestliner superhawk 1700

Trim tabs that are used too aggresively or are too aggressive can reduce rpm, speed and reduce mpg.Some have discovered that best speed and mpg are with the tabs fully retracted.
I should point out that a flow meter is necessary to tell actual fuel use.Difference usually measured in tenths.

 

[timdan94]

Re: 115 merc 4 stroke on crestliner superhawk 1700

I ordered the rubex 4 in 13x15 and wow what a difference. I'm now getting 38mph at 6400 rpms. The boat now jumps on plane and will actually be able to pull up a skier. It seems like a different boat and it doesn't blow out quite as bad as the 3 blade did.

 

[Robbabob]

Re: 115 merc 4 stroke on crestliner superhawk 1700

Simple, glad it worked out for you.

 

[sschefer]

Re: 115 merc 4 stroke on crestliner superhawk 1700

Steelspike is correct. Don't go throwing anything at it until after it's broken in. Give it 10 hours of proper break-in and then see what shakes out. You boat is maxed out with a 115 and a 115 4 stroke can act like a 90 two stroke out of the hole. The top end doesn't change simply because RPM's are RPM's and Pitch is Pitch. Optimally, you're motor should run between 6000-6400 RPM.

Four strokes don't suffer anywhere near as bad from lugging as two strokes do because 4 strokes have valves to hold the fuel in the cylinder the correct amount of time. However, it's not a good idea to lug any engine so after the break-in try a 4 blade 16 pitch prop and drop down an inch in diameter. I think she'll like it.

 

[timdan94]

Re: 115 merc 4 stroke on crestliner superhawk 1700

Steelspike is correct. Don't go throwing anything at it until after it's broken in. Give it 10 hours of proper break-in and then see what shakes out. You boat is maxed out with a 115 and a 115 4 stroke can act like a 90 two stroke out of the hole. The top end doesn't change simply because RPM's are RPM's and Pitch is Pitch. Optimally, you're motor should run between 6000-6400 RPM.

Four strokes don't suffer anywhere near as bad from lugging as two strokes do because 4 strokes have valves to hold the fuel in the cylinder the correct amount of time. However, it's not a good idea to lug any engine so after the break-in try a 4 blade 16 pitch prop and drop down an inch in diameter. I think she'll like it.

The boat is rated for 140 hp so I'm not maxed out on hp. The black max props (13x17 & 13X19) that were given to me with the boat were terrible. The hole shot was terrible and I"m only getting 5500-5600 rpms @ 43mph with the 13X17. The boat blew out the props with very little trim out. I had troble getting a tube on plane with 3 people in the boat so it would never get my fat 200lb carcas up on skiis so I had to do something about the prop. I tested the rubex 4 prop today with full fuel, full livewells, and normal gear and hit 6400 @ 38mph with just me in the boat. The blow out issue was lessened and the boat jumped on plane. If after break in it starts to overrevv I'll buy another prop for normal loads and keep the one I just bought for skiing where I need the extra get up and go. I don't know why they sell boats without hour meters on them it would make breakin and maint easier.
I appreciate everyones help and advice.

 

[HSR]

Re: 115 merc 4 stroke on crestliner superhawk 1700

I run a 2008 1700 superhawk w/115 efi 4S Merc.With the stock 13.75X15P aluminum I pull consistent 6000-6200 at speeds from 40-45(solo)mph as per speedo.Tried a few different props and our boats are just a little underpowered but can still perform quite well but need to hit 6000+ for good performance.

 

[MXZx800]

Re: 115 merc 4 stroke on crestliner superhawk 1700

Curious if you lifted the motor to 2nd or 3rd hole?
I posses a similar unit 2010, 115 merc 4 stroke on Crestliner superhawk 1700. The best I can obtain is 41.2 mph using two GPS units running in the 2nd motor hole, Vengeance SS (48-16988A46) 18 pitch at 6200 rpm, elevation 1113 ft, ? tank of fuel and an extra ~300lbs in the boat.
Tested 1 Al & 5 SS props so far with minimal difference, speed only fluctuates 2.8 mph and rpm adjusts accordingly to pitch. Majority of the props tested run over 6000 rpm. Hole shot is always good and the SS props are quieter & smoother except for the Laser II 19p.

 

[timdan94]

Re: 115 merc 4 stroke on crestliner superhawk 1700

Curious if you lifted the motor to 2nd or 3rd hole?
I posses a similar unit 2010, 115 merc 4 stroke on Crestliner superhawk 1700. The best I can obtain is 41.2 mph using two GPS units running in the 2nd motor hole, Vengeance SS (48-16988A46) 18 pitch at 6200 rpm, elevation 1113 ft, ? tank of fuel and an extra ~300lbs in the boat.
Tested 1 Al & 5 SS props so far with minimal difference, speed only fluctuates 2.8 mph and rpm adjusts accordingly to pitch. Majority of the props tested run over 6000 rpm. Hole shot is always good and the SS props are quieter & smoother except for the Laser II 19p.

Right now its in the second hole. I'm afraid that if I go higher I'll have more problems with the prop slipping.

 

[timdan94]

Re: 115 merc 4 stroke on crestliner superhawk 1700

Please listen to what I say when I suggest getting 20-25 hrs on your rig first...I've been down this road before as a prop consultant doing set-ups on 4-strokes, which has fooled me many times, especially seeing a 17P so low in rpm on the 115 on that boat.
May I ask what altitude above sea-level you are operating at?
We've been running 17P's on the 1700 with 90hp 4 stroke Mercs' and seeing about 6150-6300 w/eng. in third hole with a good SS. I have not tried to go any higher. But these engines also have all had 40-50hrs + before attempting to fine-tune the set-up.

what stainless props have you guys been using.. I'm looking to get one this year and have no idea what prop or pitch to get?
thanks
Dan

 

[timdan94]

Re: 115 merc 4 stroke on crestliner superhawk 1700

I'm still having issues with getting the engine to run full rpms with a reasonable prop. I would like some opinions on the set up of my motor. here are a few pictures

Does my engine sit lower than it should?
Thanks

 

[MXZx800]

Re: 115 merc 4 stroke on crestliner superhawk 1700

Motor looks like it is sitting properly in position #2, four strokes do seem to sit lower than i.e.2 stroke optimax when you are looking at the cavitation plate relationship to the hull.
I raised my motor to the #3 hole, testing SS Trophy Plus 17p & 19p resulting in no top end gain, rpm?s increased, when cornering blow out occurs easier, steering was tougher at top speeds. Definitely need a four blade for this setup. Excellent out of the hole acceleration.
Dropped motor back to hole #2, tested a SS Turning Point Express (Patriot-PA2) 19p, it is too much prop but runs 42.2 on gps @ 5800 rpm. This seems to be the best performing prop out of the nine I have tested. Hopefully this up coming week I will get my hands on the 17p SS Turning Point to test.

 

[pokman]

Re: 115 merc 4 stroke on crestliner superhawk 1700

why not give a 16p vengeance a shot. I run one on my 115. Mine is a 03 so it is different from yours, but I think it is about perfect for my engine, if your running right at 6400 now you may only lose a couple hundred rpms and gain some top end. I think powertech also makes a 16p 3 blade.