Adding a larger than spec motor only because I have it - not to go faster - questions

[WA-Newb]

I currently have two boats that I am working on and now two decent running motors both with matching kickers.

First boat is a 1960 Glasspar Cuddy Cabin (Seafair Sedan) currently with no motor...It came to me with a 1970's Merc 150 (Tower of Power) which I sold.

Second boat is a 1975 18 foot Seaswirl Trihull with a 1987 Johnson 120...now running good (thanks to all new ignition).

Just this week I bought a 1978 (I think) Evinrude 200 complete setup and I need to know if either of the boats I have could handle this motor ok.

I am not into going fast by any means..I am actually a slower than average boater and only use the boat for salmon fishing which means a 2-6 mile run each way.

I guess my main concerns are the extra weight..and possibly fouling the plugs or having a hard time planing if I am not giving it full throttle.

If the Nada guides are close to accurate here are the weights of the motors I have (or had):
'79 Mercury 150 = 349 lbs
'79 Evinrude 200 = 386 lbs
'87 Johnson 120 = 365 lbs

Now some extra info:
The 1960 Boat with the old Mercury 150 did around 32 MPH with two people.
The Seaswirl with the '87 Johnson 120 did about 36 MPH with same two people.

Does anyone have any advice or information that can help me decide on whether I can try to use this Evinrude 200.
Ideally it would be on the Cuddy Cabin boat but open to either right now.

Would rather find the right size motor of course but can't do that until this 200 sells...and it would see a lot easier if I could give them a test run

Thank you.

 

[Chris1956]

Re: Adding a larger than spec motor only because I have it - not to go faster - quest

That 18 footer should have a capacity plate. It should be close to 150HP. Any idea what the max rating is?

Normally a 1960 boat would have had twin 40HP motors, or a single 75HP motor, as that was largest avail back then. I would think more than 75HP would be bad.

 

[WA-Newb]

Re: Adding a larger than spec motor only because I have it - not to go faster - quest

I couldn't read the upper half of the plate but I did finally find the model and it shows the max for that boat was a 150.

From Boat: 1975 Seaswirl Boats Falcon Bowrider

This Seaswirl outboard runabout has a fiberglass hull, is 17.67 feet long and 86 inches wide at the widest point. The boat weighs approximately 1350 pounds with an empty fuel tank and without any gear or passengers. The maximum horsepower we have listed for this outboard boat is 150 hp

The cuddy cabin boat has no plate but I have been in contact with one of the founders of one of the old Glasspar clubs who owns a marina and loves these boats..says the Johnson 120 would be ok but nothing bigger.

Again I know I would be going over the max rated but do not wish to use the motor at full throttle so it;s just weight issue which is an extra 40 or so pounds and having to run the motor at less than full throttle...I just don't know if this 200 should be ran at lower RPMS or if it will even get on a plane if trying that.

I also do have some interest in the 200 today so maybe I can just get it sold and find the right motor...just want to know my options still though since this is a nice 200.

Thank you.

 

[Sea Rider]

Re: Adding a larger than spec motor only because I have it - not to go faster - quest

If both 150 and 200 weights same you can use it, just throttle less or restrict throttle mechanism to throttle less than wot.

Happy Boating

 

[Scott Danforth]

Re: Adding a larger than spec motor only because I have it - not to go faster - quest

iboats and those of us on here can not, and will not condone overpowering a boat. if your involved in an incident, you can be found at-fault and your insurance will most likely not cover you.

Its not a weight issue, there is actually a formula for calculating the vessel max power based on the length and width. This is what the coast guard uses

 

[JimS123]

Re: Adding a larger than spec motor only because I have it - not to go faster - quest

This question is the most asked around here. It was asked and answered 84 times this week alone, thus a lot of google room to see what the general consensus is.

 

[Frank Acampora]

Re: Adding a larger than spec motor only because I have it - not to go faster - quest

That Glasspar, while a beautiful classic hull, has a full width transom with no reinforcement. That transom is NOT particularly sturdy. Unless you do some heavy duty repair and reinforcement to the transom, DONT mount the 200. In fact, don't mount it at all. Yeah, you say you won't use full throttle but there will come a time when you will need it or think you need it, or simply want to try it to see. The road to hell is paved with good intentions.

Believe me: I worked on one with a 100 Merc and it was PLENTY fast. You will not be disappointed with performance attained with a 120.

Take this advice from a guy whose motto is: "Too much horsepower is never enough."