1987 Looper v4 140 RPM only 4000

[THEFERMANATOR]

Originally Posted by Skools Out

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. 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.

[Skools Out]

Originally Posted by Skools 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.

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

[Skools Out]

Originally Posted by nymack66

I was told my engine is a 1987 E140tlcua,

Originally Posted by nymack66

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.

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.

[THEFERMANATOR]

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.

[Skools Out]

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.

[THEFERMANATOR]

Originally Posted by Skools Out

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.

[spareparts]

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

[nymack66]

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 ?