TOPIC: motor decision advice please...

Trying to decide between 2 motors... both in good working condition

it would be going on my 14' gw invader drag/ski project so either has plenty of power

1963 merc 650 65hp for $450
or
mid 70's merc 70hp for $750


advice please...

Either motor would push your boat nicely, my personal preference would be for the 65 hp, 1963. Thats likely driven by my youth in the 60,s. Some folks don,t like the 70 hp, I have no experience with them. Ultimately your decision.

I'm not sure if either motor mentioned has enough HP to carry the bow on the GW Invader - if it is like the one in the attached picture with an old Evinrude hanging off the transom.
But,...If it is like the smaller GW Invader - like the other one shown with a 50 hp Merc - either the 650-4 or 70-3 would be O'Plenty of HP.
Thom

i prefere the 4cyl 650 over the 3cyl 70

I would prefere the early 60's merc the black and chrome looks awsome

Def the merc 650, and when it gets booring pull the pwr head and drop on a merc 1000 pwr head......its a direct fit and about 15+ mph faster, and there are plenty of long shaft 100hp motors out there cheep. The 70hp should be a long shaft. I dont think they made them in a short? they have a bad rep of overheating, 2 carbs on a 3 cyl didnt make much sence either. But this is just my opinion.

Go with the 63 650. I have a 68 650 I'm going to run this summer. I'm not too keen on those early 3 cylinder Merc 70hp.
Like Ponyboy said. It is a direct swap with the 1000 power head if you get bored.

Dr Frank... what do you know about that top boat??? Ive been looking for someone that actualy knows about them, Ive only found 1 other online and it was an old sale ad. The guy I got the boat off, had a 70hp on it and claimed it was scary fast. If neither motor will work, I will look for something higher powered.

As for the astetic's that 650 was definatly the winner.

go with the 4 cylinder 650 over that 3 cyl 70 any day. It is not for looks either it is just a better motor.

First off the 650 is wayyyy better looking, but as for speed the 70 hp triple will more than likely eat its lunch. A merc 500 that weights significantly less will nearly keep up with a 650 mec on a small boat due to the weight penalty and larger drag of the bigger lower unit.

The 650 is kinda a portly old girl. From the power head down its the same as a 1000 merc. Good if you plan on making it a 1000 someday, but bad due to excess weight for its HP class. Its way over engineered. This was a cost cutting measure to make two birds with one tooling set up.

I have a 1965 1000 and a 1965 650 and was surprised how close in weight they were. The 650 is packing some weight.

Ok the 70 hp triple is kinda ugly but it is build on a much lighter platform and has some real snort IMO if running correct. Many people down right loath these 65 and 70 hp triples. I have only worked on one in my life and it ran well and was pretty ballsy.

So if its entirely speed your after either get the 650 with the hopes of transplanting a 1000 powerhead on it. Or get the lighter 70 hp triple.

If its looks, well I favor the 650 by a long shot. The 70 triple looks like a plastic lunch box.

Conrad

In other words, if 65-70hp isn't enough, the 650 is a powerhead swap away from 100+hp, versus a complete motor swap with the 70.

yes it is.

I'm not trying to highjake this thread but I have a 65 merc for my 14' jetflite, which is the max rating. How much would the 100hp powerhead add to the weight of the motor?

I think my 65 650 weighed in at 245lbs and my 65 1000 weighed in at 275lbs. Its been awhile since I weighed them in the shop, but I was amazed how close they were. Both short shafts. And the 650 was Magneto only no stator.
Conrad

I agree with all the comments. The four cylinder 650 is a big girl, but she carries it well and is elegant as all get out. I have three of them, a 64', a 67' and a 69', not a dog in the bunch. The early models were not that speedy but the later red striped 650's were damn hard to beat speed wise, as they improved the powerhead and ran a different gear ratio. The triples? Well, the less said about them the better.

Glad to hear that about the Red Band 650s I have a 68. It is on an 85
Areocraft Trihull.

i had a 68 650 on a 18ft revline cabin, was great but when i put a 73 850 on in was even better stronger faster and to my suprise more economical much so.

I hope to get it running on the Areocraft and run her as a Rat Rod. Even though she is a trihull.

I'll get rid of the Fin

Jetboat,
I had this one when I was a young kid an didn't have the knowledge or skills required to identify and correct this hull so it would stop prancing.
I had over 200 lbs of sand in the bow and an ugly howling v4 65 hp on it.
If I had it today I would identify why she romped so I could throw away the sand bag and run a minimum of 80 hp - probably as much as a healthy 1150.
She had a lot more boat (weight due to hull design) fore of the helm and narrowed back to a quite narrow transom.
In some respects she has some similarity to a small Allison or Viper and I believe that if the bottom of the hull was trued up in the right way and she had enough HP you could carry the bow and really fly.
Before I sold mine I put a Mark 25 Merc (20hp) on it and turned the kids loose.
It was perfect for them. It ran about 22 mph on plane with no romping, etc.
I had lost track of it for years, but my nephew spotted her dying in a back yard and recognized the paint job.
I approached the current owner, but it wasn't for sale.
Thom

thats some good info, better than most of what I have found so far. Its actually making me wonder how much power I really want to throw on this thing. My goal is only 40mph but, I want it to be a safe 40mph. I figure a boat this small going that fast is kind of like riding a 10 speed behind a semi.

I think Ill forget about the 70hp and maybe call about the 65. though, I did find a killer deal in the glassifieds on a 85 Johnson with tilt and trim... just too bad its 6hrs away. Must resist the need for speed..........

if 50mph is what you are looking for i would go for a 50hp merc.it would be lighter and is quite dependable should hit that speed easily. and much lighter.check and see if the boat needs a short or long shaft before getting the motor.

I can run either short shaft or long, the transom of the boat is cut down for a short shaft (factory) but like the others I have found, has a riser plate installed for a long shaft motor.

I just happened upon a 65hp mid 70's merc on a boat, the guy wants $500 for everything and it has a trailer that is allot better than mine and comes with power tilt and trim. Its on my way home so Im going to look at it. Problem is the running condition is unknown as the guy took it as payment for some work. Said he doesnt know anything about it.

power trim is worth that it will fit all 3 4 and 6 cyl with shocks.

Im just iffy because its a 3cyl and I have read the threads about those on here...

Im still waiting for a call back on the 4cyl

Hi, I have a 14 and 15 GW Invader. My Father had a 15 when I was a kid with a 1972 100hp Johnson and when I had it I had a 140hp and it was a high 70mph boat according to police rader back then how accuarate that was who knows. It was fast and alot of fun. I did straighten and true the bottom.
I bought a 14 and am restoring it and found a 15 in VT and bought that. I have a 140 johnson for the 15 and am looking for a 100 or 115 merc for the 14. How is the transom and core in the 14. The 15 did not have core. Both my boats have been modified new core in the 14 new stringers along with extra foam stringer and new transom with knees and removed splash well. The 15 has new stringers, transom, knees and a penski floor to save some weight over plywood. If it were me I would look for a bigger motor. I redid my floor in the 14 the way you did. If you are looking for seats similar to the fiberglass buckets they came with I can give you a number. I would like to see more photos of your boat. My email is This email address is being protected from spambots. You need JavaScript enabled to view it. If you go to yahoo groups under GW Invader I have photos of my boats the 15 was a great example of how not to rebuild a boat by the previous owner. Most of the 14's I saw as a kid had 75hp motors and up.
Good Luck Joe