lee
Slightly Obsessed
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Here's my de-restriction of a 2.5hp Tohatsu outboard.
The 2 stroke Tohatsu 2.5 and 3.5hp outboards use no longer available and haven't been for years due to EU restrictions in place, now they are replaced with 4 stroke versions, like many I prefer the 2 old stroke versions, smaller, more reliable and more torquey.
People have been buying up the 3.5hp for the last few years and its hard to find a good one now. People tend to not bother with the 2.5hp because they want more power so the buy the 3.5hp ones, the problem now is that the 3.5hp ones that do come up for sale are most often well used as they are being used as everyday all day engines were the 2.5hp ones that come up have generally only been used as tender engines to larger boats, I picked up a as new 2.5hp yesterday with only 5 hours on it so I've de-restricted it back up to 3.5hp.
The 2.5hp Tohatsu is a restricted 3.5hp engine, The block, valves, head and carburettor and jets are all the same on both models, 2.5hp is restricted by a larger carburettor intake that only allows half opening this can be removed and cut down to allow full opening. You also have to cut the plastic on the throttle cover to allow the throttle to be pushed right pass the rabbit.
The other difference between the engines is that they made the 2.5hp direct drive with no gearbox, this makes it lighter and less to go wrong.
So if you want a good little engine for your small boat or canoe, keep away from the abused 3.5hp ones and de-restrict a 2.5hp
All 2.5hp Mercury, mariner engines are restricted 3.5hp as well as, some only have a restricting plate with a smaller hole fitted inbetween the carburettor and inlet, simply remove the carburettor and removed the plate, others like the Tohatsu below take a bit longer (10 mins) to de-restrict.
To to de-restrict the Tohatsu 2.5hp outboard.
Restricted:
Intake valve modified. (About 8mm cut off)
Valve refitted, carburettor now fully opens
Longer cut made on throttle cover to allow throttle to go right open
Mint engine
Running at slowest setting
Video on de-restricting the Tohatsu 2.5hp with before and after power test. (not me)
The 2 stroke Tohatsu 2.5 and 3.5hp outboards use no longer available and haven't been for years due to EU restrictions in place, now they are replaced with 4 stroke versions, like many I prefer the 2 old stroke versions, smaller, more reliable and more torquey.
People have been buying up the 3.5hp for the last few years and its hard to find a good one now. People tend to not bother with the 2.5hp because they want more power so the buy the 3.5hp ones, the problem now is that the 3.5hp ones that do come up for sale are most often well used as they are being used as everyday all day engines were the 2.5hp ones that come up have generally only been used as tender engines to larger boats, I picked up a as new 2.5hp yesterday with only 5 hours on it so I've de-restricted it back up to 3.5hp.
The 2.5hp Tohatsu is a restricted 3.5hp engine, The block, valves, head and carburettor and jets are all the same on both models, 2.5hp is restricted by a larger carburettor intake that only allows half opening this can be removed and cut down to allow full opening. You also have to cut the plastic on the throttle cover to allow the throttle to be pushed right pass the rabbit.
The other difference between the engines is that they made the 2.5hp direct drive with no gearbox, this makes it lighter and less to go wrong.
So if you want a good little engine for your small boat or canoe, keep away from the abused 3.5hp ones and de-restrict a 2.5hp
All 2.5hp Mercury, mariner engines are restricted 3.5hp as well as, some only have a restricting plate with a smaller hole fitted inbetween the carburettor and inlet, simply remove the carburettor and removed the plate, others like the Tohatsu below take a bit longer (10 mins) to de-restrict.
To to de-restrict the Tohatsu 2.5hp outboard.
Restricted:
Intake valve modified. (About 8mm cut off)
Valve refitted, carburettor now fully opens
Longer cut made on throttle cover to allow throttle to go right open
Mint engine
Running at slowest setting
Video on de-restricting the Tohatsu 2.5hp with before and after power test. (not me)