powerhead interchangeability with a 1978 140 hp

[crabbydad]

Which year powerheads are interchangeable with model number 140883C. was very surprised when I looked up the model number on the powerhead of my 1989 sportcraft with a seadrive to find out the powerhead was a 1978 evinrude 140hp. A friend a work has a 140hp, late 70's, but I'm not sure of the year, I"ll have to check, but I'd thought I'd ask here which years would fit. I thought I read that 78 was the year they changed so a 77 or earlier wouldn't fit.

 

[V153]

A '77 140 will fit. '76 and earlier will not.

 

[crabbydad]

thanks, I think he might have a 77,

 

[SparkieBoat]

if he has the midsection for that 77' you need to get the exhaust tuner out of it. that was the only year for those special ones. the racers all want them, as they help with high RPMs but just so you know, in 1985 they changed how they rate HP, so a pre 1985 140 is about the same as a post 1985 115. also those late 70s 140s used a smaller crank shaft. I would rather have a post 1985 115 if i had a choice but they 77 140 would work if it has good compression.

 

[crabbydad]

it is a complete motor, he rebuilt it several years ago and never used it. assuming the boat originally had the same model year powerhead, 1989, so it actually has less hp then when new? the boat definitely seems underpowered. With just me on it, it takes quite a bit to get up on plane and if anyone is in the back of the boat they have to move towards the cockpit to get on plane

 

[SparkieBoat]

no the 140 will be about the same as whatever came on that midsection that you have. maybe it originally had a 115 on it. the post 1985 140 and 120 were completely different motors and would not change out. but if you had a 78 140 on there the 77 140 will fit. as far as getting on a plane faster you could try a different prop and or some trim tabs. how big is the boat?

 

[crabbydad]

the boat is a 1989 Sportcraft WAC with a seadrive, 2650# dry. the motor my friend has is a 1977 140HP. he rebuilt it, bored .030 over. He only ran it on the boat for about 15 hrs. he bought a bigger motor and took the 140 off. he fogged it and it hasn't been run for 6 or 7 years. its just sitting on a stand. My plan is to fix the powerhead on the boat. I pulled the powerhead and am in the process of taking it apart. I broke a ring in one of the cylinders. the compression is 120 in the other 3, so I am planning on boring the bad cylinder, replacing that piston and all the rings. I was mainly interested in my friends 140 in case my block is damaged or if I don't feel I can rebuild mine. But, he said I can have it for $50, so I am going to jump on it. I Should have my factory service manual in a day or so.

 

[SparkieBoat]

so is that a 20 foot boat? if so I would consider that underpowered. I have seen 140s on boats that big but they were the newer looper motors and have more power than the smaller V-4s like you have. I prefer something more like a 200 or a 225 on something that big. but I like to be able to run fast (45-55) if I want too.

 

[crabbydad]

yes its 20' long. max speed was around 25. I was getting ready to sell it because I bought another boat, 1989 grady tournament. Now I have to fix it so I can sell it. I guess its better it broke down before I sold it. I would hate to sell it then it break down. Hopefully I'll get it put back together and running right

 

[SparkieBoat]

good luck. I buy and sell old boats and motors just as a side hobby. you should check your local market and see what is selling and for how much. I have found it very difficult to get a decent price for old boats and motors. I have just been parting stuff out seems to be the only way to sell it. I just hate to see you put too much hours and money into that boat and have to almost give it away. those sea drives are particularly undesirable because you cannot get the parts for them anymore. but you just never know, I have seen stuff sell before that I thought would not.

 

[crabbydad]

I know, but I don't think there's much chance of me selling it the way it is. its a decent boat in good shape. I will clean and wax everything. Clean boats sell a little quicker.

 

[SparkieBoat]

yes they do.. shiny sells much better.