Motor size for an older 16ft fiberglass

Good luck everyone has their own opinion mine is 50 would be low 90 would be high anything in the middle would work great
 
Looks like my old Glaspar.Made in Bullhead Arizona. Mine had a 1961 Volvo 80 hp Inboard outboard ,was a bit of a dog.Guy who bought it of me pulled the motor and put a Johnson 70 on it never talked to him to see how it performed. Was a very soft riding boat in rough stuff. Ran into the same boat at my cabin and talked to the owner who had a 90 Yamaha 4 stroke on it and was pretty happy. I always thought an older 70 Yamaha 2 stroke small block would have been a good match. The Volvo was good on fuel but pretty heavy and I couldn't get parts anymore. Good luck!
 
You should be able to find an old Evinrude/Johnson 90 hp V4 dirt cheep that will meet your needs for years to come.

http://bellingham.craigslist.org/boa/5947155564.html
Looks super clean. If compression checks out, those crossflows are very strong engines and really simple to work on. Thirsty on gas compared to 4 stroke but more torque out of the hole, and at that price you can afford a lot of gas.
 
Local option that could be a look if you can haggle down the price and can either do the work yourself or have access to reputable and cost effective mechanic...

https://comoxvalley.craigslist.ca/boa/5951389345.html

I would be careful with this option, if memory serves me right the older parts 70 hp has a difrent powerhead than the newer white one does. Easy way to check is to have a look at the exhaust cover, newer one will have one gasket the older one will have multiple gaskets. Not easly inter changeable if this is the case. Also the spline's on the drive shaft might be different as well.
 
I've found one for sale at Deans Marine in Duncan. It's a 1990 Evinrude 70hp. It's on consignment for a customer but the shop has looked it over. Their e-mail says:

"We checked the compression (115, 115, 120) spark tested (looked good) We did notice the leg oil should be replaced soon. The battery terminal was corroded, so we replaced it. Ran it up, and it runs good, and idles good."

Pic can be viewed here: http://www.deansmarine.ca/Parts-and-service/for-sale-by-owner/

They're asking $1000 with controls.

I kind of like the idea of buying something that a shop has already had a look over and fixed anything they noticed already. Has anybody had dealings with Deans Marine?

I have heard these are solid motors, and I would likely disconnect the VRO and pre-mix as that seems to be the thing that gives people grief over time.

Thoughts?
 
The VRO (variable ratio oiled) weren't all bad.
the principal was actually a good one. The problem was on some models the
low oil light would fail to come on and the operator ran the motor out of oil.
simply disconnect and premix your fuel.
 
Last edited:
I run a 140hp Johnson VRO on my 17.6" and she flies. I've premixed the gas oil since I've had it as I too read horror stories about siezed and exploded motors.
 
VRO problems came from the first generation gas/oil pumps in the mid 80s. Second gen and beyond were fine. They'll run OK on premix, but only OK. Ignition and carburetion were designed/calibrated for VRO's lower oil mix ratio at slow speeds - all the way down to 100:1 at idle (hence the acronym VRO: Variable Oiling Ratio). It wasn't simply about convenience, the concept was to reduce plug fouling and improve idling. Even well-tuned premix two strokes have a tendency to stall going in and out of gear, this is why.
 
VRO problems came from the first generation gas/oil pumps in the mid 80s. Second gen and beyond were fine. They'll run OK on premix, but only OK. Ignition and carburetion were designed/calibrated for VRO's lower oil mix ratio at slow speeds - all the way down to 100:1 at idle (hence the acronym VRO: Variable Oiling Ratio). It wasn't simply about convenience, the concept was to reduce plug fouling and improve idling. Even well-tuned premix two strokes have a tendency to stall going in and out of gear, this is why.

Yep. Can be pretty smoky at idle. Use Amsoil mix oil and it'll cut the smog down significantly. Not sure about others but mine seems to run fine. And I save a bunch of space inside by not having an oil res in the back of the boat.
 
The problem with the VRO system is that it has very little variable oiling...it is a two stage pump..either 50 to one or 100 to one. Not sure at what rpms it flips from one to the other but no where near as good as the gear driven Yamaha system that is fully variable through out the entire rpm range. Obvously if the VRO pump doesn't switch from 100 to 1' to 50 to 1 when you open it up the pistons are going to start to seize. I bought a new 70 HP in 1987 and it blew up after 10 months.
 
There is an element of variability right in the pump though, because it's driven by crankcase pressure. That changes according to rpm, so the pump capacity is directly proportional to engine rpm. (Same as most fuel-only pumps on 2 strokes)
 
Well, I picked up the 70hp evinrude on the weekend, and spend the last couple evenings getting it all rigged up. Everything seems to run well on muffs, but no sea trial yet. I have a few more little things to work out before hitting the water to test it out. The motor came with the VRO already disconnected so I don't know if there were issues with the system, or if the previous owner just decided to do away with it. At this point I'm just going to leave it alone and pre-mix.

The steering all hooked up OK but it's pretty stiff and has a fair bit of slop in it so I'm likely going to replace that next. Not sure exactly the direction for that but that will be another post.

Thanks everyone for their advice and input here. It has been most helpful!
 
If you overpower your boat and have an accident, your insurance policy (providing you insured the boat, a good idea if you're into water sports) can be voided by the insurance provider. Just saying... :-(
not true in all cases. im insured with beacon, with a declaired hp of 300, slightly over the max rating of 165. all good as long as you disclose
 
Merc that owner ran out of oil, top left. Owner wanted to keep the oil pump and it ran great! Installing boysen reeds didn't hurt!IMG_0890.JPG
 
70 Should be a good fit for you. I had a 16' with a 50, and it was slow to plane. Dolphin Finns improved that rather significantly, but she still couldn't plane with over 3 people aboard. My 18 now has a 100, and it's more than enough. However, running motors at lower RPM's does increase lifespan. That being said, Mine had 1500 hrs when I sold her with plenty of life left, and cruised at 4700.
 
Back
Top