What engine would you put in your boat?

[Michigan boarder]

On 2/18/2016 at 1:14 PM, Woodski said:

@MB: I would ask about the 1257 but IMO that is probably a bit too much pitch and would result in probably too slow an engine speed at the surf/boarding speeds (lower speeds & ballasted), but just a guess on my part, it would be fine for slalom and barefooting but still spin slower than typical. What I would ask, is whether they have / make a 449 or 515 with .135 cup. I customized my prop with added cup and really like it, ended up with just under 1:100 speed/RPM and the added cup improved the holeshot. You have plenty of power under the curve to spin a big prop, the extra pitch probably would dampen the response of changing throttle position. I would ask them if they have any test or feedback on that when discussing the 1257.

Well, you were pretty right about that.  I talked with Jim Thelen for about a half hour about props, my boat, the 454 Echelons, what we do, looked at the numbers, etc. etc.  In the end, he thinks I'd be best off with a 425 (13x13) with .135 cup.  The more we talked I realized that JBFoot uses his boat for barefooting, and surfs behind a V-drive, so he is not plowing water at surf speed like I intend to.  Jim said my stock cast prop is more like a 13x12, so moving it to a 13x13 will likely drop 400RPM off, putting me under or close to 5,000RPM at WOT.  Adding some cup, and he feels it will be what we are looking for.  Really good guy to work with, sounds like they'll let me try two at a time for quick comparison and return the one that isn't the one.

On 2/19/2016 at 7:15 PM, JB-FOOT said:

The 1257 was an absolute winner on my boat

But that's for strictly footing, right?  How is the hole shot with long line?  I tend to think I'll try out the 425 cupped and the 1257.

[JB-FOOT]

Footing is 90% of what the boat does

10% slalom

Perfect for both.

Pulls like a freight train

Runs smooth as silk

[Michigan boarder]

So, I had a long phone call with ACME a few weeks a go, and we went with the 425 and standard cup of .080.  We put the boat in the water last week and this weekend I finally got a chance to record the speed and RPM info, thought I'd post an update/comparison.  The speed was again measured via phone GPS.  Here's what we have:

Speed          Original prop RPM          ACME 425 (13x13 .080 cup)

20               2290                             2080

25               2650                             2355

30               3130                             2785

35               3750                             3180

40               4450                             3760

45               5330 (WOT)                  4330

49                                                   4900 (WOT)

The holeshot is better, the RPM's are down at top end, and we gained 4 mph on top end.  And I'm back to 1:100 with the MPH:RPM, so I think we found the right prop for this engine/boat.  There is definitely no more slippage, it takes off hard.  Even when cruising along at 30mph, bury the throttle and it is GONE.  Not that I have a reason to do that very often, but it feels really good as we were testing it thru the whole power band.

[ahopkins22LSV]

That sounds like a perfect fit! And an absolute blast to drive!

[Michigan boarder]

But, now I have two new issues:

1) At speed, when turning sharp the steering sticks, easy to turn into the turn, hard to turn out of the turn.  There is some play in my rudder and I'm guessing that it needs to be replaced.  Winter project.

2) The throttle works well and as I roll it forward the boat accelerates.  But there is a spot just before the secondaries open up where it feels like it bogs down, or misfires.  Not real bad, but it seems like there is something going on there.  Then I roll the throttle past that small spot and it continues to pull hard.  ??

[Woodski]

@Michigan boarder:  Prop curve looks much better, perhaps a bit of slip at the top end but otherwise looks really good. 

1.  check the vertical play in the rudder and if you have some, add a washer on the topside to lift the rudder a bit. what is happening is the prop wash, now different from previous prop, is sideloading the rudder causing it to bind.  I had similar issue and corrected with a washer on top.  Also, lube your steering cable with ATF from the tiller end, disconnect and gently pour some ATF down the sleeve / cable gap and articulate the wheel back and forth to work the fluid up the cable, that does wonders to loosen a stiff cable.

2.  Sounds like a fuel calibration issue, are you still using the Weber carb?  If yes it could be many things, I would say a needle or needle spring change might be a cure for that.  The secondary air valve may be opening too soon causing a slight lean spot.  You might also benefit from a accelerator pump change.  I recall you swapped out the carb for a newer one, perhaps the vendor has some suggestions on changes.

[Michigan boarder]

15 minutes ago, Woodski said:

@Michigan boarder:  Prop curve looks much better, perhaps a bit of slip at the top end but otherwise looks really good. 

1.  check the vertical play in the rudder and if you have some, add a washer on the topside to lift the rudder a bit. what is happening is the prop wash, now different from previous prop, is sideloading the rudder causing it to bind.  I had similar issue and corrected with a washer on top.  Also, lube your steering cable with ATF from the tiller end, disconnect and gently pour some ATF down the sleeve / cable gap and articulate the wheel back and forth to work the fluid up the cable, that does wonders to loosen a stiff cable.

2.  Sounds like a fuel calibration issue, are you still using the Weber carb?  If yes it could be many things, I would say a needle or needle spring change might be a cure for that.  The secondary air valve may be opening too soon causing a slight lean spot.  You might also benefit from a accelerator pump change.  I recall you swapped out the carb for a newer one, perhaps the vendor has some suggestions on changes.

Thanks Woodski - I remember you mentioning the washer thing now.  Man, if it's that simple that would be great.  So, looking at this pic, I would drop the rudder so it is below the tiller arm, and then put a washer at the top of the rudder underneath the tiller arm?  On the engine - I'll pull the plugs and take a look.  Yes, I did swap with a rebuilt of the same Weber carb.  But, we did dyno with this carb and I have not adjusted anything on it since the dyno.  And I do not recall this issue last year, but then again this prop is making a huge difference, maybe noticeable now.

[Woodski]

@M-B:  correct on the washer process.  On the bog, the new prop is loading the engine more so that is probably the difference.  The bog may not have been apparent on the dyno.

[tvano]

36 minutes ago, Michigan boarder said:

And I do not recall this issue last year

no doubt an unnecessary reminder but, given the amount of work that was done on your rig last year, it's about time to buzz through everything you an reach and make sure it's all snug.

may be worth putting on your 'list o things to do at lay-up this fall, too.

sure is a  pretty rig.  good stuff.

[Michigan boarder]

18 minutes ago, Woodski said:

@M-B:  correct on the washer process.  On the bog, the new prop is loading the engine more so that is probably the difference.  The bog may not have been apparent on the dyno.

If it's actually a bog.  I need to take it back out and run it again, it's very slight, might even be a throttle cable.  Should I be able to feel more resistance on the cable when into the secondaries?  It happens as the throttle is going past the horizontal plane, as it goes to like -10 degrees.

21 minutes ago, tvano said:

no doubt an unnecessary reminder but, given the amount of work that was done on your rig last year, it's about time to buzz through everything you an reach and make sure it's all snug.

may be worth putting on your 'list o things to do at lay-up this fall, too.

sure is a  pretty rig.  good stuff.

Good idea, very good idea.  I will do that.  Latest engine pic:

[Woodski]

@M-B:  The friction buttons in the throttle unit tend to eliminate the feel of the actual throttle linkage at the carb, so probably not.  I do not feel that point on my setup in the throttle itself, you might feel it from the actual boat or seat of the pants aspect when the secondary's open.

[Michigan boarder]

1 minute ago, Woodski said:

@M-B:  The friction buttons in the throttle unit tend to eliminate the feel of the actual throttle linkage at the carb, so probably not.  I do not feel that point on my setup in the throttle itself, you might feel it from the actual boat or seat of the pants aspect when the secondary's open.

It's definitely something I feel in the throttle, but it's always been there.  I just assumed that was normal (my first/only V8 inboard).  It goes down easy, then I hit resistance for the last 1/4 throttle.  Hmm.

[Woodski]

@M-B:  It might be the friction buttons or surface they rub on binding a bit, the unit can be disassembled and cleaned if needed.  Also, looking at the latest picture it might just be worth a WOT run w/o the spark arrestor, in my case with what looks to be the same one, it was a source of airflow restriction at the top end.  With 383 cubes, it will request more air than a 350 assuming cam/heads can flow it.  I ended up making my own with more surface area but did try a Zenith version off a big block that worked pretty well.

[Michigan boarder]

Just now, Woodski said:

@M-B:  It might be the friction buttons or surface they rub on binding a bit, the unit can be disassembled and cleaned if needed.  Also, looking at the latest picture it might just be worth a WOT run w/o the spark arrestor, in my case with what looks to be the same one, it was a source of airflow restriction at the top end.  With 383 cubes, it will request more air than a 350 assuming cam/heads can flow it.  I ended up making my own with more surface area but did try a Zenith version off a big block that worked pretty well.

I agree, another on the "to-do" list.

The new steering wheel is really good too!

[MadMan]

The purpose of the accelerator pump is to cover up the bog that all carbs have when the throttle is moved quickly.  I noticed in the photo you posted that you have one more adjusting hole in the accelerator pump linkage (the hole closer the pivot point).  By changing to that hole you would be getting the maximum fuel the accelerator pump can discharge.  This might be enough to cover the rest of the bog. 

[Michigan boarder]

On 6/1/2016 at 7:47 PM, MadMan said:

The purpose of the accelerator pump is to cover up the bog that all carbs have when the throttle is moved quickly.  I noticed in the photo you posted that you have one more adjusting hole in the accelerator pump linkage (the hole closer the pivot point).  By changing to that hole you would be getting the maximum fuel the accelerator pump can discharge.  This might be enough to cover the rest of the bog. 

Wow, forgot all about this.  Do you mean the other visible hole on the red end of the cable (to the right)?

[martinarcher]

Nope, he's talking about the metal linkage just forward of the throttle linkage.  You've got a hole that is closer to the pivot which would provide a bit more throw and more fuel when you put the hammer down.  

[Michigan boarder]

Just now, martinarcher said:

Nope, he's talking about the metal linkage just forward of the throttle linkage.  You've got a hole that is closer to the pivot which would provide a bit more throw and more fuel when you put the hammer down.  

Got it.  The hole about 1/8" above the spot that it is currently in, right?

[martinarcher]

You got it.  

[Woodski]

@Michigan boarder:  Correct because what you want to do is change the ratio of the accelerator pump squirt (more) for the amount of throttle plate rotation (or throttle application) so it richens the mixture.  When you do that, you will also want to note if there is a mid acceleration bog or flat spot as the accelerator pump quits feeding additional fuel to the mixture.

[Michigan boarder]

On 6/1/2016 at 7:47 PM, MadMan said:

The purpose of the accelerator pump is to cover up the bog that all carbs have when the throttle is moved quickly.  I noticed in the photo you posted that you have one more adjusting hole in the accelerator pump linkage (the hole closer the pivot point).  By changing to that hole you would be getting the maximum fuel the accelerator pump can discharge.  This might be enough to cover the rest of the bog. 

 

On 3/8/2017 at 12:05 PM, martinarcher said:

Nope, he's talking about the metal linkage just forward of the throttle linkage.  You've got a hole that is closer to the pivot which would provide a bit more throw and more fuel when you put the hammer down.  

 

On 3/9/2017 at 12:58 PM, Woodski said:

@Michigan boarder:  Correct because what you want to do is change the ratio of the accelerator pump squirt (more) for the amount of throttle plate rotation (or throttle application) so it richens the mixture.  When you do that, you will also want to note if there is a mid acceleration bog or flat spot as the accelerator pump quits feeding additional fuel to the mixture.

Delayed update, but yes, this did fix the problem!  Very smooth acceleration now, thanks guys.  This is increasingly important now that I am footing more regularly, and likely to have multiple footers behind this boat soon.