Motor swap

[mikeroe]

I have a tracker 18' fs with a Johnson Gt150. I'm wanting to downsize my motor to a 115. The 150 is a lot more power than I even come close to utilizing plus the additional weight causes me some trim issues. My boat is rated for a maximum of 150 hp. I've had few offers but before I accept anything I would kind of like to have a ballpark idea of the value of my motor. Plus since it has a Johnson motor should I try to stay with an OMC type motor because of the throttle and linkages. I realize my going to a smaller motor just sounds odd but I don't need all that power as a novice boater.

 

[SigSaurP229]

Re: Motor swap

What year is your motor. Ok so the truth of the matter most likely is that I referred you to this great forum with my trade offer. The other truth of the matter is I have been shopping 150 hp engines in East and Middle Tennessee for about 3 months and I have seen your exact motor for as low as $600 with a fresh carb rebuild to as high as $1800. It is about the condition and what someone is willing to pay. The other part of this is actually finding a good motor to put back on your boat and doing a proper rigging job

 

[drrpm]

Re: Motor swap

Its probably easier to just sell that boat and buy one with a smaller engine. Usually a boat with an engine at its max rating is more desirable. You don't have to use all the power but its there if you want it. I'm not sure what the trim issues are but they should be fixable either by adjusting the motor trim or at worst by putting your cooler in the bow.

 

[SigSaurP229]

Re: Motor swap

Yes I suggest staying with the same brand engine not just for simplicity of linkages and controls but also so that u are reusing the same bolt pattern on your transom and not putting new holes in your boat

 

[Home Cookin']

Re: Motor swap

Although I think bolt patterns are standard, it's a good idea to stick with the same brand for the controls and ease of installation. However, I understand some of the plugs in OMC change through the years sop look into that.

And you may find a used motor with controls, including on a junk boat.

You are, however, trading a used motor with known (or few) issues for a used motor with unknown issues.

I don't think downsizing is a bad idea in itself and it is a lot easier to sell your present old motor while it is runnnig instead of after it has problems. But there is the risk of buying the replacement motor and then not getting what you want from yours, plus the time factor (which is a money factor). So the question of whether it is worth it has too many unknowns.

 

[SigSaurP229]

Re: Motor swap

Older mercs and omcs have different bolt patterns

 

[jimmbo]

Re: Motor swap

Older mercs and omcs have different bolt patterns

OMC has used the Current pattern since 1960. Merc started in 1984 with line 4 and 6s and followed with the V6s in 1985 or 86

 

[SigSaurP229]

Re: Motor swap

Correct which is a good reason if the boat currently has an OMC to stick with OMC.

 

[82rude]

Re: Motor swap

op has a gt 150 as of now, so I doubt very much he wants to go for a older merc, so any newer merc will have the same bia bolt pattern.op didn't state how new he wanted to go so it kind of leaves a heck of a lot of leaway.lets say 1995 and newer,then all motors will have the same bia pattern that would be acceptable for that boat.only problem is the early 1980 or late 1970 mercs but im just assmuming he doesn't want to go that old.any motor ive ever sold ive included the controls and as for cables for shifting and throttle their easy to change and cheap if you need a different length.if it was my boat id stay with omc just because I like them more than any other make .as a matter of fact I bought my last to death takes me motor and it was an etec

 

[anzomcik]

Re: Motor swap

Like stated earlier, not sure what the trim issues are, but downsizing a motor in my experience would make the trim issue greater as you are dealing with 30% less power, pushing a smaller prop, and paying more attention at maintaining speed.

Example, I had a 14 foot aluminum with a 25hp ran good but took a while to plane out (relative to the motor and hp I was dealing with) I hung a 40hp on that boat, while the 40 weighed more I planed in like 3 seconds.

Another example, my current rig came with a 70hp Johnson, it took a lot of trim work and maybe 6-8 seconds to plane, but over all decent performance once moving. However frustrating the amount of work it took to dig out. So I repowered and maxed my HP at 115. Its night and day drop the hammer and go, I still trim the motor but I the rig isn't nearly as sensitive to being at the correct spot in order to plane out.

I think it would be a terrible mistake to unbolt that 150 and hang a 115 on it. For a beginner it might seem like a lot, just don't drop the hammer, you do not have to run the motor WFO go half throttle, build your confidence slowly and by mid summer you will be perfectly fine and comfortable.

If you do not follow my advise (do what you like) at least entertain this thought. Buy good used 115, hang it on the boat and run it but DO NOT sell the 150 YET wait a season or so. Because you might find you do not like the 115 and all you would be out is a weekend to switch it back. If you sold the 150 to buy the 115 there is no getting your good motor back in the event you are not happy.

 

[dazk14]

Re: Motor swap

Like stated earlier, not sure what the trim issues are, but downsizing a motor in my experience would make the trim issue greater as you are dealing with 30% less power, pushing a smaller prop, and paying more attention at maintaining speed.

Example, I had a 14 foot aluminum with a 25hp ran good but took a while to plane out (relative to the motor and hp I was dealing with) I hung a 40hp on that boat, while the 40 weighed more I planed in like 3 seconds.

Another example, my current rig came with a 70hp Johnson, it took a lot of trim work and maybe 6-8 seconds to plane, but over all decent performance once moving. However frustrating the amount of work it took to dig out. So I repowered and maxed my HP at 115. Its night and day drop the hammer and go, I still trim the motor but I the rig isn't nearly as sensitive to being at the correct spot in order to plane out.

I think it would be a terrible mistake to unbolt that 150 and hang a 115 on it. For a beginner it might seem like a lot, just don't drop the hammer, you do not have to run the motor WFO go half throttle, build your confidence slowly and by mid summer you will be perfectly fine and comfortable.

If you do not follow my advise (do what you like) at least entertain this thought. Buy good used 115, hang it on the boat and run it but DO NOT sell the 150 YET wait a season or so. Because you might find you do not like the 115 and all you would be out is a weekend to switch it back. If you sold the 150 to buy the 115 there is no getting your good motor back in the event you are not happy.

Well said.

The control issues are fixable - guaranteed. Just post with your issues. It could be nothing more than a sloppy steering cable or helm - which would bug you with a 115hp, as well.

A 4 blade prop can do wonders for tracking....

Good used known condition motors are like gold.

 

[mikeroe]

Re: Motor swap

Thanks to everyone's input on this matter. The way my boat is set up now I can on plane quickly. I think now if I downsize on the motor there's to many reasons why I may not be happy with the outcome as opposed to the few reasons to do it. Being a novice, I should allow more time for learning curve as far trim issues go. My motor was rebuilt 2 years ago and a new stator at the end of summer. I don't know enough about outboard motors to feel comfortable buying a used from an individual. So it makes more sense to keep what I have.

 

[greenbush future]

Re: Motor swap

Thanks to everyone's input on this matter. The way my boat is set up now I can on plane quickly. I think now if I downsize on the motor there's to many reasons why I may not be happy with the outcome as opposed to the few reasons to do it. Being a novice, I should allow more time for learning curve as far trim issues go. My motor was rebuilt 2 years ago and a new stator at the end of summer. I don't know enough about outboard motors to feel comfortable buying a used from an individual. So it makes more sense to keep what I have.

Great choice, you have a really nice set up on paper, learn it well then decide. Like others said, unknown used outboards can be a real pain. You know what you have now, rare is the case where anyone ever wants less power, for what it's worth.