Whaler 13 Repower

Clayton, New York
Hull
1974 BW 13
HIN
2B3990
Transom
20 in
Max HP
40
Weight limit
200 lb

Updated Saturday 5 September 2026, 12:34 PM · transom height inferred, not yet measured

Good news first: we can answer the marina's shaft length question without anyone going near the boat. The old Johnson's paperwork settles it, and the tape measure your brother took backs it up. The bigger finding is that on a 13 foot Whaler the motor decision is not really about horsepower at all. It is about weight, and that changes which motor we should buy.

The marina's question, answered

Joan's original Johnson owner identification card gives the motor as model J25ELCT, serial 05785802, dated 12 September 1983. Johnson's model codes are not arbitrary. Each character means something, and the fourth one is exactly what he asked for.

J
Johnson
25
25 horsepower
E
Electric start
L
Long shaft, 20 inch
CT
1983 model year

The L is the answer: the boat is rigged for a 20 inch transom. The hull year agrees independently, because Boston Whaler raised the 13's transom from 15 to 20 inches in 1973.

The measurement at the boat

Hugo's brother put a tape on it, hooked at the cavitation plate just above the prop and run up the leg. That is the right way to check it: on a correctly mounted motor the cavitation plate sits level with the bottom of the hull, so cavitation plate to the top of the transom is effectively the shaft length.

Tape measure hooked at the cavitation plate of the Johnson outboard and run up the leg to the transom, with the boat in the water
Hooked at the cavitation plate, above the prop. This is the cross-check on the paperwork: the paperwork says the boat is set up for a 20 inch shaft, and the tape is the physical confirmation. Read the number where the tape crosses the top of the transom board and that is the figure to give the marina.

Weight, not horsepower, decides this

The hull is rated to 40 HP with console steering, so horsepower is not the limit. The limit is that a 13 is stern heavy. The published ceiling for weight hanging on the transom is about 235 lbs, and the number owners actually use is 200 lbs. Past that the stern squats and the boat gets unpleasant sitting still.

Here is why that matters. The motor coming off is a light 1983 two stroke. Modern four strokes are all heavier, and they are not heavier by the same amount.

Motor weight against the transom limit

Rigged dry weight, pounds. All candidates are 20 inch shaft with remote controls and electric start.

1983 Johnson J25ELCT coming off
115 lb
Yamaha F25LC Our pick +26 lb
141 lb
Suzuki DF25ATL +43 lb
158 lb
Mercury 25 ELPT +65 lb, weight unconfirmed
180 lb
Any 30 HP four stroke Over the limit
220 lb
  • On the boat now
  • Candidate
  • Past the limit
Show as a table
MotorWeightvs the JohnsonSource
1983 Johnson J25ELCT115 lbbaselineon the boat
Yamaha F25LC141 lb+26 lbconfirmed
Suzuki DF25ATL158 lb+43 lbconfirmed
Mercury 25 ELPT180 lb+65 lbestimate
Any 30 HP four stroke220 lb+105 lbclass typical
The Tohatsu MFS25 is the lightest 25 made, at 128 lbs, but it is sold here only as a 15 inch tiller motor, which is the wrong shaft for this boat.

What we should buy

Yamaha F25LC, new, roughly $5,000 to $6,000 rigged

It is the only 25 that gives us all four things we want, 20 inch shaft, remote controls, electric start and power trim and tilt, at 141 lbs. That is 17 lbs lighter than the next best motor rigged the same way, and about 40 lbs lighter than the Mercury. On a stern heavy 13 footer that difference is the whole argument.

Put plainly: it adds about 26 lbs over what is already hanging there, so the boat will sit and run the way the family remembers it. That is not true of the heavier options.

The used option worth watching

A low hour Evinrude E-TEC 25 in 20 inch remote trim turns up around $2,000 to $2,500 and is light. The catch is that BRP has left the outboard business, so parts and dealer support are winding down. For a boat that has to start reliably for kids, owned by someone who is not local, that is a real risk. Worth it only if it is cheap, close by, and the marina looks at it first.

About the hydraulic steering

Chris asked for hydraulic, and it is worth saying honestly: at 25 HP it is probably not what we want, and the reason is fit, not power.

Hydraulic is not too much for a 25. BayStar is rated to 150 HP, so a 25 will not trouble it. The problem is physical. The 13 has a notched transom and a shallow splashwell, and the hydraulic ram has to clear both through full tilt. Motors under 70 HP often need up to an extra inch of splashwell clearance, which on a 13 is tight. It has to be measured, not assumed.

At 25 HP a rotary SeaStar Safe-T QC with a 9 foot cable steers this boat with almost no effort, costs a fraction as much, and is what most 13s run.

The one real argument for hydraulic

It gives no feedback, so engine torque never tugs at the wheel. With kids learning, that is a genuinely nicer helm, and a fair reason to spend the money. Just measure the splashwell before ordering anything.

What we need from you

The tape measure photo covers most of the first one. Two things still open.

The number at the top of the transom

From the photo, read off where the tape crosses the top of the transom board. That single figure is what the marina needs to quote the right shaft.

Photograph the console and controls

He asked for these to quote accurately. They also tell us whether the existing control box and cables can be reused, which is real money either way.

One thing to add when you write back to him: ask for the actual rigged dry weight of the exact motor he proposes. Given everything above, that number matters to us as much as the price, and if there is a meaningful weight difference between what he can get, we want the lighter one.