Evinrude 9.9/15 carb - still won't plane

[moorpark]

I'm trying to plane a 14 1/2' Sea Nymph deep vee hull (FM141 series) and in spite of my efforts at tweaking the mechanical trim, my best effort is just under 10 mph indicated and no plane. The bow high attitude really creates a wake, so I know it's not pushing the boat as it should. Besides trying a smaller prop, does anyone know of an engine shop that can put a little more lust in this power head, short of replacing the entire motor?

 

[corm]

Re: Evinrude 9.9/15 carb - still won't plane

Hi Moorpark,<br />Some Sea Nymphs have a very narrow transom<br />with round chines so they don't plane very well. If your motor is tuned up you may need a stingray or similar deviece to aid in planeing. The 15HP carb doesn't always work.<br />It depends on the year of the motor. I don't have any books at home but can look it up at<br />work with year and model no.<br />...have fun...corm

 

[moorpark]

Re: Evinrude 9.9/15 carb - still won't plane

Originally posted by corm:<br />Hi Moorpark,<br />Some Sea Nymphs have a very narrow transom<br />with round chines so they don't plane very well. If your motor is tuned up you may need a stingray or similar deviece to aid in planeing. The 15HP carb doesn't always work.<br />It depends on the year of the motor. I don't have any books at home but can look it up at<br />work with year and model no.<br />...have fun...corm

<br /><br /><br />The motor was manufactured in 1997 as was the Sea Nymph. The tach indicates it is running right at 4000 rpm and it idles smoothly, in spite of the larger carb. It starts quickly, runs with minimal vibration and doesn't appear to be missing or hesitant at any speed. In fact, for a 2 stroke, it doeesn't even demonstrate loading after relative long periods of idle operation when I open up the throttle. <br /><br />The motor's model # is: E10RELEU<br />and it's S/N is: GO4289904. <br /><br />By the way, what's a sting ray? Is that the flat tail looking thing I've seen in Overton's catalog that attached down around the L.U. Does it look like a whale tail contraption that provides a horizontal surface directly above the prop?<br /><br />moorpark

 

[corm]

Re: Evinrude 9.9/15 carb - still won't plane

Hi Moorpark,<br />Yes the stingray is like a whale tail,but has more tail lift. A 15HP should rev up to 6000RPMs, so your a little short.The newer boats have a wider transom. Ididn't have time to check out what I wanted to,but will try.<br />...have fun...corm

 

[Capt DHD]

Re: Evinrude 9.9/15 carb - still won't plane

Hello;<br />The intake plate is different on the 2 engines as well as the carbs. Your poor performance may be associated if all you changed was the carb.<br />A good running 15hp should plane the boat your describing pretty easily I would think.<br />The leaf plate assy pt# you need is #390050.<br />Hope this helps<br />Rob

 

[moorpark]

Re: Evinrude 9.9/15 carb - still won't plane

Boy! You wouldn't believe the difference! I took both yours as well as Corm's advice, with the following results:<br />1. The tachometer setting on the back of the instrument was set improperly. The boat originally was delivered with a 40 hp Johnson, so the tach was set by OMC for it, thus, it was reading far lower than it should've. Trouble was, the original dealer said there were no adjustments on the tach, and further, "9.9 or 15 h.p. motors don't have adequate alternators to run a tach reliably, so they might indicate lower than normal, so you just have to live with it!" What rubbish. Last visit I'll make to that dealer. I set the tach to 5 as advised me by another OMC dealer and voilla, the tach reading came up to 5000 with a 10" pitch prop. Still 10 mph though and bow hig, hmmmm.<br />2. I replaced the prop with an 8" pitch.<br />3. I installed a doel-fin on the cavitation plate.<br />4. Yesterday, with a radar gun, (I don't trust low speed readings on pitot tube speedos,) I was clocked at 18 mph and the boat was planing beautifully! In fact, the bow attitude never rose like it did before the whale tail was installed. The gadget really works! RPM is now up to almost 6000 at max.<br />5. Don't know about the leaf plate assembly yet. I guess I'll have to order it and see if it continues to make a difference. Where does it go, under the carb?<br /><br /><br />

Originally posted by Capt DHD:<br />Hello;<br />The intake plate is different on the 2 engines as well as the carbs. Your poor performance may be associated if all you changed was the carb.<br />A good running 15hp should plane the boat your describing pretty easily I would think.<br />The leaf plate assy pt# you need is #390050.<br />Hope this helps<br />Rob

 

[moorpark]

Re: Evinrude 9.9/15 carb - still won't plane

Corm: Please see my reply to Captain DHD (Rob) as it also applies to your help as well. What a difference a little knowledge can make when misinformation, in this case from a dealer, gets in the way of desired results. You two made all the difference in the world. Now, my little bass boat, although not a speed demon, at least performs admirably and planes smoothly. I can only imaging what it would've cost me if I had simply given it to the original dealer and said, "fix it." I owe you both. Mucho thanks. I'm certain I'll have other questions as the winter months go on... Later, **** <br /><br />

Originally posted by corm:<br />Hi Moorpark,<br />Yes the stingray is like a whale tail,but has more tail lift. A 15HP should rev up to 6000RPMs, so your a little short.The newer boats have a wider transom. Ididn't have time to check out what I wanted to,but will try.<br />...have fun...corm

 

[corm]

Re: Evinrude 9.9/15 carb - still won't plane

Great Moorpark,<br />Just leave some fish in the lake for me.

<br />The intake manifold goes between the carb and the reed plate.(without looking up the part no.)<br />...have fun...corm