First time boat owner with a few questions

94toy22re · Aug 11, 2024

I bought a motor first 15hp Yamaha 4 Stroke with a 20" transom, bought it for $500. This past week I found a 98 1436 lowe for $600 with trailer!

I noticed in the add that this Lowe had a built up transom I thought it should be ok, but when I attacked the motor it looks like it hanging 2-3" lower than it should. Will this be ok or do I need Jack plate or look for a different motor?

Also with the way they mounted the rear seat in the center, I don't under stand how they operated the motor from this position, I either need to remove the seat or move it it to the left or right side!

Wanting to use this on a few local lakes and eventually get into some nearby rivers.

LDUBS · Aug 12, 2024

Aw shoot. I'm going to answer with a question. What is the measurement from the top middle of the transom to the bottom of the transom.

airshot · Aug 12, 2024

Just a couple observations here...the operator probably turned the seat sideways to steer, but that seat could be moved or replaced to suit your needs. Something I do is.... to tilt the motor so the cav plate is parallel to the bottom, use a straight edge ! Once the cab plate is parallel....is it within one inch of being above or below the bottom ?? If it is then your good to go, however you might be able to fine tune it by trying it slightly above the bottom. You need a gps to check your speed and preferable to have a tach to check rpm. When fine tuning your ear is not accurate enough to know when your gaining or loosing speed. How the weight is placed inside your boat will also make a big difference ! Looks like previous owner raised the transom for a taller motor already. Keep us posted on your findings....

94toy22re · Aug 12, 2024

LDUBS said:
Aw shoot. I'm going to answer with a question. What is the measurement from the top middle of the transom to the bottom of the transom.

18"

LDUBS · Aug 13, 2024

94toy22re said:
18"

Thanks, and I should have said when you measure transom height it is a vertical measurement, not literally along the angled transom. No worries if you didn't -- I don't think it is going to make a big difference in your case.

See the chart below (from Yamaha). You are kind of in no-man's land between a short and a long shaft. Like @airshot says, if the cav plate is within an inch, life is good and you could stop there or fine tune it to maximize performance. If you are 2" to 3" below the bottom of the hull there will be a lot more drag and likely the boat willl be slower. I don't know how being deeper might impact control (steering the boat) at high speed (shouldn't be any issue at slower speeds).

You can run it "as is" with the motor too deep. Performance will be less than optimal, but if you are happy then life is good. Alternatively, and what I would do, you can raise the outboard a couple inches to improve performance. There are a lot of different ways to accomplish that. Again see Airshot's comments about fine tuning for performance.

By the way, if you run it as it is set up, I recommend you attach a short safety chain to the motor so that if it comes unclamped it won't go in the water. The way the clamps are sitting right on top of the weld bead, I would be worried about it shaking loose. Keep an eye on that. The clamps should sit flush. Even better if you can bolt the motor to the transom.

airshot · Aug 14, 2024

Or....could a piece of plywood be attached to the transom for the motor to ckamp

thill · Aug 16, 2024

Run it and see how it performs.

I had a tin boats that only ran well with the motor deeper than it "should" be. I blocked up the motor to get the cavitation plate flush with the bottom and it constantly blew out. Removed the blocks and it ran great.

I've also had boats the other way. Looked like a long shaft but ran much better with a short.

Again, run it first before deciding

94toy22re · Aug 16, 2024

So I wasn't happy with the modified transom, so I order a jack plate and put it on, its still not perfect but its defiantly solid now. I still need to take it out on the water, so update coming soon!

lckstckn2smknbrls · Aug 16, 2024

With the setback of the mini jacker you can raise the motor an extra inch or more.

94toy22re · Aug 16, 2024

lckstckn2smknbrls said:
With the setback of the mini jacker you can raise the motor an extra inch or more.

What do you mean by setback?

lckstckn2smknbrls · Aug 17, 2024

94toy22re said:
What do you mean by setback?

The jack plate does 2 things first it raises the motor second it moves the motor to the rear 4 inches. Thats setback. You can drill out a few more of the dimples on the jacker and raise the motor an inch or more. My motor is about 2 inches above the bottom of my hull.

TriBull · Aug 18, 2024

I really like having a jack plate! I used tree cutting wedges (green) to get my motor trimmed right. I especially like having the space on the interior transom for mounting my boat hook & dive ladder. I also run with my fuel cell up front for balance…

lckstckn2smknbrls · Aug 18, 2024

TriBull said:
I really like having a jack plate! I used tree cutting wedges (green) to get my motor trimmed right. I especially like having the space on the interior transom for mounting my boat hook & dive ladder. I also run with my fuel cell up front for balance…

The tree wedges are an interesting idea.

TriBull · Aug 18, 2024

lckstckn2smknbrls said:
The tree wedges are an interesting idea.

It’s how I was able to get my boat to stop porpoising. I tried a few different angled wedges until I got it zeroed in…

Crazyboat · Aug 18, 2024

In my opinion you are definitely too low. Either add a jack plat or bolt some ply wood on the back to raise it to the right height.

94toy22re · Aug 19, 2024

Took it out for the first time last night, with two 180lbs passengers hit 21mph on the 2nd trim setting, which seems to be about right for the weight and motor. I still think the motor is to low, with the way I bolted the jack plate in I can move it up another 3/4”-1” and maybe add a wooden wedge!

LDUBS · Aug 19, 2024

Pretty good result for a 15 HP and a loaded 14' boat. It will be interesting to hear how it does with the motor raised another inch. If the motor is working well on the 2nd trim setting, I question you need a shim. If you think you can't trim it down enough, then a shim could help.

thill · Aug 20, 2024

Not bad at all for 15 HP. Congrats! Now use the boat often.

First time boat owner with a few questions

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