1987 Looper v4 140 RPM only 4000
 

Guys , Any idea why I can only get 4000 RPM at WOT ? Compression is 130/120 across all ports,
What size Jets do I need to install on my Carbs ? Currently 58D installed.
New everything on the engine,coils,plugs,wires,harness you name it minus pistion and rings !! . See photo at www.nymack66.com , I am restoring this baby..If I can get an album here it will be great I will move my pictures up

58D is for a 120HP, not a 140HP. Should have 61Ds in it. How many screws do you have holding the throttle blade onto the shaft? Somebody may have put 120 carbs on it, or a 140 cowling. And 4000 is no where near enough, i turn mine right up to 6100(rev limiter for 85, 86+ is 6700). These loopers need to turn at least 5600 WOT. Are you sure your tach is right?

Good question on the Tach , New Tach what setting do i turn it to on the V4 ?

12 pole IIRC. Are you sure that it is a 140 and not a 120? What is the number on the block welch plug?

It is a 140 for sure base on the power Pack etc
The gauge is Teleflex Vector 7000 RPM Tachometer
For 4, 6, or 8 cylinder gas engines
or 4, 6, 8, 10 or 12 pole outboard engine

Set it to 12 pole. And the 120 and 140 are almost identical, the only differences are the exhaust tuner, carbs and reeds. Power packs and everything else is the same, even the timing. The only differences cannot be seen without some disassembly.

Tach/RPM Issues
 

Just verify the setting on the Tach it is a Telflex Brand and it is set to 6 which per the instructions is for and outboard 2 stroke v4 engine, As for the High Speed Jets they are 64D. Is this an issue with low RPM 4000 max at wot ? I have spare jets I can swap back to 61d please let me know

Most all of the JOHNNY-rudes 2,3,4,6,8 cylinder outboards run on a 12 pole setting, as well as MERCURY V-6's and many others. Is setting 6 for 12 poles? Also what are the numbers stamped on the carbs? I went and checked the catalog and an 87 could have 59D's or 61D's, and if it was a late engine it could have 63D's in it. I know 86 was 61D's which is what my carbs had stock, but 87 was the last small bore and 88 was large bore(displacement, not carbs). It gets confusing with these things sometimes.

Thanks for all your help , Hopefully this helps
 

Yes the Tach is set to setting or dial 6 which equals to a 12 pole.
I was told my engine is a 1987 E140tlcua, The carbs I remove have 397907 & 397908 is stamped on em, The high speed jets the dude remove is 61d he told and bill me for complete replacements on all carbs , The carbs on the engine has no stamp on em , As for the high speed jets on the engine currently I am not 100 percent sure but I remember him saying 64d or something like that . I will remove and check em tomorrow afternoon . My Idle is all 28 , Intermediate is 16 starboard 20 on the port side as per the manual. What's on yours across the board ?

hook a shop tach to it and check it against your tach, what prop are you spinning?

I remove a SS 14x3/8 x 19 only going 3000 to 35000 rpm, I install a 14.8 x 17 aluminum it is a 15 spline prop 3 blade
Remember I am restoring this boat I have no base line to work with , Please see www.nymack66.com for some photo etc , I am stump in regards as to why the engine is not giving me the RPMs everyone is talking about !!

I would try a 15 pitch stainless wheel myself, but somethin don't sound right here. Are you sure your hitting on all cylinders under load? Is the timing set to 18 BTDC @ 5000 RPM's(very important that it is set at 5K as the power pack has about 4 degrees of advance in it with RPM due to trigger and stator outputs). Loopers are CRITICAL of timing. I would get you a bo0ok and go through the carbs top to bottom, make sure the plastic bodies are not warped. Then set the timing and go from there. To bad you aint closer, I'd help you figure it out as I'm fairly proficient with the V4 90 degree loopers.

Timing and link and sync was done by local dealer Boat Tune. I can only assumed it was done correctly
Carbs re-built inside out
Carburetor 397907 & 397908
Idle Air Bleed #28
High Speed #61D (I am not sure what he replace this jet with )
Intermediate #16

Those sound like the early 87 same as 86 carbs. These are the ones I am running. I'm jetted with 63D's main, 14's intermediate, and 34's(or 36's not 100% certain on which) for idle. This works excellent in mine running 50%1 pre-mix with PENNZOIL synthetic blend oil. But I have some very mild porting done in the exhaust ports behind the sleeves, and my air box has been slightly ported as well and I have a .020 over bore. I still trhink there is a problem with your link and sync or in the timing department. These engines are CRITICAL of timing. 2 degrees to much and meltdown happens, 2 degrees not enough and your 140 is a 115. THEY HAVE TO BE DEAD ON! I learned this one the hard way:cen:.

Update
 

Here is what installed
Idle=28
High=64D
Intermediate=Starboard side=16
Intermediate=Port Side=20
Note per the Parts Manual this odd sizes for the Intermediate is normal for this engine
I will test it on the lake hopefully on Sunday

Update2
 

I forget to mentioned I change the High Speed jets back to 61D per repair manual , I will test and post the results

Wrong lower unit you have a V6 lower unit none of the short shaft 20 inch motors had 15 spline lower units, they had 13 spline. Only the 25 inch 120/140 motors had 15 spline lower units. It could still be a 120 power head. My 120 and my 2 twin 140's both have 62D jets.

They did offer the bigger lower unit on 85 and some 86 140's, seen em with my own eyes. And I have 2 140 lower units that are both 13 spline V4 units. Your model number comes out to a 20" shaft, but you said before IIRC you said you have a 25" leg. Your carb numbers come out to an 86-early 87 140 carbs, but it could still have a 120 tuner and reeds which would give you a 130 I believe. I think you need to verify your tach, and then check your timing.

right ferm 13 spline but he said he has 15 spline that's either a 25 inch lower unit or a V6 which he has neither of. no 15 spline were on V4 motors with 20" shafts.

I've seen 2 of the 20" legs with the 15 spline shaft on the 140's. They both had the 2.25:1 ratio in them as well that came in the hybrid V6 leg. The reason I wonder about what he really has in his engine is he said he has a 25" leg and his engine number has the L not an X for a 20" leg. Sounds like some parts swapping has gone on with this here engine.

sound like a Frankenstien motor. I reember the 140 seadrives had the big lower unit, OMC ran a special on the motor assembly(every thing but the Seadrive bracket) for repowering an existing set up for a while back in the late 80s. They were selliing the motors for about what a new powerhead cost. We sold quite a few, just left the swivel bracket off the old engine, and put the seadrive stuff on, kept the standard OB cowl and lower covers

Update
 

Guys , lets face it maybe the lower unit was swap out for a v6 gearcase 15 spline , If this is the cause for my lack of RPM at WOT 4000 max then I have a lower unit from 1978 v4 140 I can bolt up to it , I brought this boat and engine from a guy that had about 20 plus motors, Who knows what he did or did not do. Please see nymack66.com page 2 and on I have photos of the engine , 140 is stamped on the block over by the throttle shift lever , I can bet it is a 140 due to the Pack, Sator, Trigger that was installed and is working. The stamp on the carbs as mentioned before is for a 140 . Could it be the gear ratio on the larger gear case be the cause ? Or should I just intall a 14x13 prop to offset the difference ?

I went back and looked at your pictures, that is definately NOT a 25" leg. It's a 20" leg, you can tell by the lower engine mount spacing. And it looks to be a V4 lower unit, not the hybrid unit that used a V6 prop. Have you counted the prop shaft splines? Or roughly what is the outer diameter of the prop hub? If it is a V4 lower, it is pretty much certain to be a 2:1 ratio which is proper for that engine. The 1.86:1 ratio in the V6 lower would KILL the V4 looper by taking it out of it's power band vs prop speed. Your prop sizes also sound like a V4 lower. I still think you need to try a 15 or 13 pitch prop. My 140 slings a 17 pitch to 46 MPH at 6100 RPM's, and a 19 pitch to 53 MPH at 5600 RPM's. It would spin a 15 pitch to around 5800 at 34 MPH on my old boat, wich would have been close to a V20 in weight.

What is your current WOT and speed at that RPM?

If your reaching 28 at 4000 RPM's your tach is pretty much dead on. 4000 with a 15% prop slip comes out to 27.4MPH. Sounds like the engine may not be tuned properly, or there is something amidst in the engine itself. You say you have 120-130 pounds of compression, have you checked this against another guage. I'm running 150-155 pounds in my 140 with a .020 over bore.

And all of the electronics are the same from 120 to the 140, no differences in between the 2 up through the 90's. The differences were internal. The numbers stamped on the block where you say is a casting stamp as I believ mine is stamped 138 there. Even if it has some 120 parts, it don't make a big difference. Both of them are torque monsters very well suited to a v I think. The problem being is these engines don't make much power up until around 3500 RPM's. If your overpropped and not letting the engine hit it's peak, it will be WAY off on RPM's. These engines are rated @5600 RPM's.

Update
 

My prop is a 15 spline for sure , I counted the splies on the shaft also,
My max RPM is 4000 , I will take it out with my GPS to clock the speed , I will post the results later

Your pictures and your model number comes out to a 20" shaft, and your certain you have a 15 spline shaft. So this means like LORD SKOOLS said, you got the wrong lower most likely. The 15 spline 20" leg lower is one RARE bird to find, so somebody probably swapped in a V6 leg. Problem being that the V4 don't have the power to spin a 1.86:1 ratio and make any power. Sounds like your gonna need another lower unit. The first thing I would do at this point is get a rough idea of your gear ratio. Take the cowling of the engine off and remove the spark splugs from the engine. Rotate the flywheel by hand until the #1 top dead center mark is lined up with the timing marker on the front of the engine and mark the 2 points. Now put the engine in forward and mark where the propeller is at. Now rotate the flywheel by hand counting the revolutions of the flywheel and propshaft until the prop makes 1 full revolution. If you rotate the flywheel just shy of 2 full turns to one rotation of the prop you have a V6 lower unit. If you get 2 and 1/4 turns of the flywheel to one revolution of the prop, you have the V4 lower.

If you have a V6 lower your engine will NEVER run right. LAND N SEA did a nice write up on prop curves vs engine power curves and how you have to match the 2. If your engine isn't at it's peak power point when the prop is at it's peak efficiency point, then it runs like crap. Simply changing your prop pitch won't give the desired effect as changing the gear ratio will. Make sure your of what your ratio is first, and then go from there.

i just looked at your pics that's a V6 lower unit for sure. i just looked at all 3 of mine none that same case. but yes same case on my many v6 225's

Thanks a million for all your help I will follow your instructions and post the results . Question I have a 13 spline 1978 140 v4 lower unit as a spare . Will this work ? I am guessing I will install a new water pump kit change the oil and bolt it up ? The current unit will not be a problem since I had it remove and service last July ..

the 78 will fit but you will have to swap the shift rods as the older one was off a cross flow and newer motor a looper they just use a different shaped shift rod that's all. they just screw in and out.

Now on a 20" lower unit the shift rod when you swap should measure 21 & 15/16 inches measuring from the surface where the gear case and midsection meet to the top of the shift rod when the gear case is in neutral.

What he said:beer:. If you have the 1.86:1 gear ratio, that 140 will never run right. It makes sense that a smaller prop should correct it, but the problem then will be that your top end will be slow even though your RPM's are there. And it will not pull well out of the hole.

You were right on, Its a V6 gearcase base on the instructions ,just like you said shy of full turns I have one complete rotation !!Thanks man , Like it sys many will be called ,few will be chosen , you are the chosen one !! The best of the bes looked at this and could not have figured this out ..Once again thanks , I will prep the spare v4 unit and bolt up ..Will keep you posted . Thanks guys keep up the good work ..

Shift Rod
 

Guys , I worked all weekend with the Shift rod issue , I am replacing the V6 gearcase see previous notes , I am now replacing it with a lower unit from a 1978 140v4 , Bolts up fine problem with the shift rod off the v6 gear case its over 22 inches in N , If I connect it to the shifter I can't shift into Forward , Reverse is fine the rod approx 1 inch 2 long,
Question is do I need to buy a new 1987 v4 140 shift rod or the shift rod from the large gearcase should work ?

The rod from the V-6 should work. Sounds to me like you have the shift rod threaded in to deep, and it is bottoming and preventing it from fully engaging forward. Thread the rod all the way in until it stops with it in neutral. Then thread it out roughly 2 full turns. Measure from the mating surface to the center of the shift rod bolt hole that connects to the shift linkage. You should have 21 15/16" of distance center of bolt hole to the mating surface. Sounds like your measuring to the top of the rod and so you would be about 2-3 turns to far in.

Another method that I have used in a pinch with virtually no tools available to me is to thread the shift rod all the way in and push downward on the shift rod into forward gear. Thread the shift rod out until you feel it go all the way down and the shift rod isn't bottoming out. Turn the rod outward until the bend faces forward and install it. This isn't the best method, but will work in a pinch.

Shift Rod
 

No Sir , no matter what I do it's just about 1/4 of an inch two long , I am going to re-tread the end of it and cut it , Stay tune :)

Are you measuring to the top of the rod, or to the center of the bolt hole? Don't go cutting it just yet, the V4 and V6 loopers use the same rods. Try threading the rod out 2 turns and see if you have forward. If your measuring to the toip of the rod, you should have 22 3/16" of length from the mating base, not the rod base. There is a 1/4" of distance from the center to the top of the rod. Also try a different tape measure as a 1/4" off in a tape measure isn't much, and this measurement MUST BE EXACT!

NO NO CUTTING STOP it is same rod as Ferm said you need to just adjust it. it should not be all the way in tight.

Update
 

If I place the rod I am trying to use (From V6 Gearcase) next to the rod from the 1978 unit it is approx 3/4 of inch more . I am confuse was it not suppose to be the same ? As for the not cutting the rod when the lower unit is bolted up and shifted in the Forward gear the connector on the end is exactly 3/4 of inch higher and will not allow me to connect it . So my thinking is the damm rod needs to be cut ! Here is what I am thinking is the unit I am removing a v6 gearcase or a v8 gearcase ? Remember I can bet on the 1979 foot I am trying to bolt up because it came from a engine with the serial numbers etc. The unit I am removing who knows maybe from a car at this point..

It is highly unlikely you have a V8 lower unit. They are massive to handle the torque that the V8 has. You can't compare the old cross-flow rod to the looper rod, COMPLETELY different shift mehanisms. Your saying reverse works tells me that the shift rod is close. Try the method pushing down on the rod and threading it out until you don't feel the shift rod bottoming out. Then mount it back up. I would say 2-3 turns out will put you close to where you need to be at. If the rod is threaded all the way in, it CANNOT go into forward. Trust me on this one. If you thread it all the way in, only neutral and reverse will engage.

Unthread the shift rod all the way, then thread it back in 3 turns. Now push the rod down until it goes into forward(you may have to spin the propshaft to make sure it goes in). Now thread the rod inward until you feel it begin to bottom out. As soon as you feel it touch the bottom while threading in, rotate it out until the bend faces forward and add 1 more turn out. Try it like that and see if it works. You cannot use the old rod as a reference of how the newq one should be.

do this show us where you are measuring and what you get. this is the only measurment on a Looper you need.

I just went out and measured a shift rod that I have in the shop. It is off of an 86 140 looper, but is for a 25" shaft. So figuring you have a 20" leg, the shift rod for yours should measure roughly 30 7/8" - 30 15/16" from the very bottom to the very top. Use a yard stick or something fairly accurate for all of these measurements. But if you have the rod threaded in all the way, then you are stuck in neutral, and the rod will stick up to high to hook up with the selector in forward.

not 30" Ferm the measurment i gave above is straight out of the OMC Shop Manual. your 25" isn't 30" the shift rod in a 25" motor is only 26 15/16 "in length installed.