No hole shot -- engine too low exhaust in the water

[mattyc]

Running an XR2 150 on a Stratos 179V fishing rig. When I'm loaded up heavy for fishing a tournament, I can't get out of the hole with the motor tucked under becuase the exhaust is under water. It just gurgles and won't wind up. I have to trim up until the exhaust is out of the water, then get on the throttle. It will wind up to 3k or so and then I start trimming down and take off.

When it's just me in the boat and the livewells are empty (about 650 lbs less), the exhaust sits out of the water, so the motor will wind up and take off with the motor tucked under all the way.

I figure I can deal with this one of two ways:

1. Right now the center of the prop shaft is 4" below the pad. I could raise the motor (I've got a jackplate with 5" setback). I'm not sure how much I could raise it and still be safe. Any ideas? No LW pickups on here and no water pressure guage either.

2. Releive the exhaust. I'm a little wary of doing this. Louder, could crack mid...?

Any other ideas??? Thanks.

[Alan Power]

You could relieve the exhaust in the LU just above the cav. plate, without the risk of cracking. Drill 3 x 1/2" holes into the exhaust passage above the cav plate.

Another thing to try is a planing foil, like a doel-fin, they look a little goofy but they work. There are nicer drag type foils that the drag race guys use if you want something a little more trick.

I wouldn't recomend raising the motor much more than a couple of inches without a water psi gauge, I'd say get one anyway, they're not expensive and easy to fit, same for a nosecone although could be a little trickier to fit, you can send your LU to some places to have them professionaly done, like bobs, titus and some others. Then start jacking it up;)

Alan

[Largemouthlou]

Most bass boats run at around 3" below the pad.. Be for you start raising the motor you need a water pressure guage if you don't already have one..

What prop are you running??

Almost sound to me that your prop needs more exhaust around it to let it spin up.. Really don't think relieveing the exhaust is your answer.. Louis

[pyro]

Your motor may also be getting a little tired if it's losing low-end power. Also, do the usual voltage tests on the ignition system, and rule out any fuel problem that can be causing the bogging.

[SportJ-US-1]

Actually lots of back pressure is better for low end preformance than none. So the exhaust in the water is not your problem. How much prop are you running and what kind of RPM are you turning at WOT? To much pitch will kill holeshot with making the top end suffer to much. Also venting the prop will help holeshot a bunch.

[pyro]

Whenever I had a full passenger load and had the occasional bogging condition, I found that a ventilated prop does NOTHING for this type of condition, since the bogging happens at such a low RPM that no exhaust is yet passing thru the lower unit. Once the motor would spin up and plane, the ventilation holes seemed to just make it rev harder as it layed down on plane. I found that a higher motor height helped mine get out of the "bog" a lot quicker.

[150aintenuff]

my motor bogs at 1500 if im over loaded due to not enough generated torque due to opening up the exahust chest and putting a 245 tuner on a 200. gained RPM up top but lost it down low so its a trade off..

[mattyc]

The motor is in good shape. Rebuilt spring '05. Fuel sys is fine, leakdown @ 'bout 3% on all cyls, ignition tests fine. Runs great xcept for this.

I'm convinced it's the exhaust bcuz when I've got a full boat, the exhaust is underwater. As I trim it up AS SOON AS it gets above the water the motor will wind up and take off like it's got lots of power. Below water, and it's a no-go.

Running a 14.25x22" thru-hub exhaust prop @ 6k RPMs WOT.

I'd like to raise the motor a little bit (easy), but I don't want to put a water press guage on it (more work). Wondering if 4" is too much below pad. Is 3 or 2" below still in the definitely safe zone? Any ideas what's not safe -- what height does the water pickups start sucking air?

[150aintenuff]

does your prop have vent holes.... if not add a 3/8" hole behind each blade and see if that helps... merc 2 and 2.4 L motors require atleast 2400+ rpm instrantly off of hammering down to effectivly build torque enough to climb on plane without bogging..

[pyro]

Whale tail would help a lot...

[mattyc]

Why/how would a whale tail help? There can't be any hydrodynamic forces coming into play at the low speeds when getting out of the hole -- can there? Is there an effect I am missing?

[150aintenuff]

keeps your nose from adding drag by rising due to accelerating out of the hole.. and climbing its own wake... and yes there are forces at that speed... enough to kill an engine... been there done that

[pyro]

Think how the boat pitches up in the air when you start to plane. The engine is deep in the water, and the boat is moving forward. Also, the engine may be "tucked in". The tail is moving forward at a 45 degree angle at this point, lifting the rear of the boat up and out of the water quickly while forcing the bopw down. At speed, it's out of the water and doesn't affect handling.

[wrechin2]

Pyro,
Would putting the LONG 150 tuner in it instead of the 200 short bell tuner help him on bottom end? I know you know alot about the XR2's.

[mattyc]

does your prop have vent holes.... if not add a 3/8" hole behind each blade and see if that helps... merc 2 and 2.4 L motors require atleast 2400+ rpm instrantly off of hammering down to effectivly build torque enough to climb on plane without bogging..

No, my prop doesn't have vent holes. How do they help the motor spin up at low RPM but not be a probelm at high RPM? Is this really a good thing to do?

Where exactly should these holes be drilled? Pics?

[Alan Power]

How do they help the motor spin up at low RPM but not be a probelm at high RPM?

Supposedly the flow of water over the hub at speed is enough to seal the holes and stop them ventilating the prop. They probably still vent the blades a bit but it realy wouldn't matter. My 2

Alan

[Hydrasports205]

Running an XR2 150 on a Stratos 179V fishing rig. When I'm loaded up heavy for fishing a tournament, I can't get out of the hole with the motor tucked under becuase the exhaust is under water. It just gurgles and won't wind up. I have to trim up until the exhaust is out of the water, then get on the throttle. It will wind up to 3k or so and then I start trimming down and take off.

When it's just me in the boat and the livewells are empty (about 650 lbs less), the exhaust sits out of the water, so the motor will wind up and take off with the motor tucked under all the way.

I figure I can deal with this one of two ways:

1. Right now the center of the prop shaft is 4" below the pad. I could raise the motor (I've got a jackplate with 5" setback). I'm not sure how much I could raise it and still be safe. Any ideas? No LW pickups on here and no water pressure guage either.

2. Releive the exhaust. I'm a little wary of doing this. Louder, could crack mid...?

Any other ideas??? Thanks.

Going to a prop with vent holes is going to solve your problem. Your engine doesn't make a lot of torque and going to something like a tempest w/ all vents open will help you jump on plane pretty quick. I'd stay away from exhaust relief and hydrofoils on that setup. Like the other guys said relieving the exhaust will decrease the backpressure and needed lowend power of your motor. Also, with the motor mounted 3-4" below the pad a foil is going to affect the running attitude of your boat through the entire range. I ran a 2liter merc on my sport for a couple of years and tried a foil...and several different props. Trophies and tempests both worked w/ the tempest being the quicker of the 2, the foil I tried was an se3000. It really improved holeshot, but with the engine mounted so low it also held the bow down at speed(lost about 5mph).(there are other good props out there this is just my opinion)

[k591]

Does the XR2 have the 150 long tuner? I had a similar issue (regular 150hp) and changed to a 200 tuner (shorter) and it helped some. Now when the boat is over loaded the same thing happens. There were some posts on drilling holes in the side of the tuner but opinions vary greatly. A Tempest with vent holes helps but when it's buried I do the same trimming out to get the revs up then in to get on plane. You may want to check your stator.

[eliminatedsprinter]

On my E-rude 150, I switched to a better prop (of the same pitch) that was ventilated and cupped and I gained a ton in both hole shot and top end. I can't be sure if the venting helped my hole shot, but it sure didn't hurt.:D

[Hydrasports205]

Venting will absolutely help holeshot if it's not excessive, try playin with the pvs plugs in a merc prop and note the effect on takeoff.

[xskid]

funny how i see this thread only one day after 200 plus hours of work came to an end with not being able to plane off my newest project. ive been working on shortening a mid. i took a 20 in. mid, cut 9 in. out, its 4 1/2 in. shorter than a standard inline shortshaft. the motor is in perfect running condition. its a 1978 1500xs powerhead with a speedmaster lower unit. the boat is a 13ft v- bottom. with xs lower unit it comes out of the hole like a rocket. the water is up to the trim cover when im sitting in it. it wont rev over 2000 rpms. when i put it on the trailer and pull up the ramp so the prop is a little out of water it revs up to 6000 easy. i also thought the exhaust is in too deep, but i also dont think its the problem. the prop is a 9 3/4 x 17 3 blade cleaver , is it too much pitch? ive never run a speedmaster and dont know what prop to run. does anyone know what prop to run on an inline with speedmaster?

[Stitch King]

This will start a lot of crap but here goes...

Get a Torque Shift prop. About $400 on ebay. Have one on my 21 Liberator for general use around the lake and towing tubers/skiers. 13 pitch on the low end and shifts up to 24 at around 3500 rpm on the tach. I now have a boat that can out holeshot anything on the lake (mastercrafts, bigblock jets) and still get decent top end. I am convinced that mileage is also improved because for normal driving you do not hammer the throttle to get it on plane.

You are running the motor deep in a fixed position so surfacing is not an issue. Also want to note that the prop needs to be kept to 3500 rpm prop shaft speed per the manual. So that means if you have 1.75:1 gears you gotta keep the tach below 6100 rpm. If you can't control yourself set the upper pitch limit higher so the motor can't pull past 6000.

This will solve your problem with only turning one bolt. Reply or PM for more details on buying the right one or setup. That part can get confusing.

[bdawg13919]

My gambler did the same thing to me once when I had a lot of weight in the boat, infact it actually stalled out. I just trimmed up on it a bit then took off. took a while to plane off but after that everything was fine. I run a 200 hp Yamaha with a 4 blade 25p FnR prop and it sits about 3" below the pad. The prop does an awesome job at planing the boat off even with a load because if I have more weight than usual i just plug one of the exhaust holes so the prop doesn't blow out. Watch out for the torque shift prop they are hard to get parts for because of a fire in their plant and there is a lot of work involved in them and if the prop surfaces then it usually throws the whole thing off. You should post this same forum on bass boat central and see what the fellas say.

[gfinch]

Fill the jack plate with closed cell foam. I used the kind the insulate walls with. Put a thin plate to cover the top and a thicker plate on the bottom. this will float the boat higher and the open plate can't scoop up water. This is a little over kill for you but heres a pic of mine.

http://img67.imageshack.us/img67/5621/fscn00496ws.th.jpg (http://img67.imageshack.us/my.php?image=fscn00496ws.jpg)

You can also use a beach ball, just put it in and slightly inflate it.

[Project Contender]

2 pennies.. I have a 150merc on a hydrostream and had the oppurtunity to run 2 props of the same type. one with vent holes and one without. The vent hole prop planes my stream in half the time. jumps right up on plane. also blows out in a low speed turn quicker...

[gfinch]

TorqueShift props are a blast. Have one, but don't use it now just chopper types, well surfaced.

[terry taylor]

Actually lots of back pressure is better for low end preformance than none. So the exhaust in the water is not your problem. How much prop are you running and what kind of RPM are you turning at WOT? To much pitch will kill holeshot with making the top end suffer to m uch. Also venting the prop will help holeshot a bunch. \LOTS OF BACK PRESSURE IS GOOD ? PLEASE EXPLAIN YOUR THEORY/ IF YOU CANT BREATH OUT LESS BREATHING IN LESS POWER.Back press. is a 2 strokes worst enemy on my omc i drilled exh. relieve holes [on mid. just below cowl straight through into tuner lots of exhaust and water idled smoother and throttle response .I should explain, These exhaust relief holes already exist on engines however drilling strait thrue into tuner gives a direct exit this greatly helps prevent loading up. We get this normaly after prolonged idleing thus the stumble and smokiness when we hit it.[backpressure]. You are having to the extreme and very quickly with tuner submerged you could try before accelerating trim engine up to put tuner above water suface[not prop exht.]rev. in neutral. This clears loadup , accelerate quickly while trimming down this should help [p.s. drilling straight into tuner as mentioned will help but you must be caustious do not reverse with relieved vents close to water surface possible ingestion if engine stalled.] hope this might help thanks.

[yanny_haulinbass]

I have a 2.4 that had trouble plainin my bass rig. I jacked it up and it helped. I added a Bob's exhaust snout and pulled the can. The engine idles better without loading up and winds right up. I switched to an over the hub and I can run 2" more pitch with twice the hole shot after all the changes.

[Hydrasports205]

I switched to an over the hub and I can run 2" more pitch with twice the hole shot after all the changes.
Yeah you switched to an overhub design....try running a through hub like he currently has and see how well your exhaust relieved motor gets up. If he goes to something thru/overhub his situation is gonna get MO BETTA. BTW on a heavy hull SOME backpressure adds needed torque to help you get out of the hole. On a heavy bass rig you take away all the backpressure and you're gonna have to run a 15p overhub to get out of the hole with w/ 2 people and full livewells.

[yanny_haulinbass]

I was speaking from experience about what worked for me. My 2.4 could not make power barried in the water with all the extra back pressure from the water level. The rpms would not climb over 2500 until the boat planed.

I was running a 24 vented Michigan wheels which absolutely sucked for hole shot, switched to a 23 small hub renegade which was better but worked even better with the engine raised, and even better with the exhaust relieved.

I then went to a 26 chopper and it is by far the best. The rpms jump from 700 to 4500 instantly and the boat is on plane in seconds. (I had tried an over the hub without relieved exhaust and it sucked, just spun and jerked for 4-5 seconds before the boat went anywhere)

Theres more than one variable acting on hole shot here. I've played with a mirage, tempest, and trophy and couldn't get it to work at any engine height with any size pvc plug on my rig. I even took em right out.

This guy should try a vented prop or a small diameter hub to get his revs up quicker, if it's not good enough, raise the engine and add a water pressure guage, and if that's not enough relieve the exhuast and go to an over the hub. It doesn't seem as though he wants to take it that far.

[terry taylor]

hi. to those who like backpressure respectfully. tap a rubber ball into the end of taipipe of your car/truck,drill a1'' hole in muffler tell us how it idles and accelerates. [food for though] [THE FIRST ONE ]

[Alan Power]

A four stroke has exhaust valves ...

[terry taylor]

HI. Yes it does and 2stoke have ports [AND THE DIFFERENCE IS],would you care to explain. backpressure is backpressure as i know it. THANK YOU.[I HAVE ADDEDTO MY PREVIOUSE POSTING PLEASE READ] THANKS.

[Hydrasports205]

If you think a wide open exhaust is a good thing on a heavy boat why dont you come take a ride in my sport w/ the offshore snout open, partially closed, and fully closed. :D

[terry taylor]

HI HYDRASPORTS205 I like your prom pic. im sure you have a nice boat and would like to visit BATON ROUGE. However i never mentioned wide open exht. but i did address with good info. My message is clear and be done with as one wishes thanks. [ I LIKED YOUR PROM. PIC.---IT DID NOT HAVE A CRACK IN IT./