Logo
FULL SITE MENU

1987 Johnson 4hp Power Upgrade

J

jbone07

New member
Hello,

I am wondering if it is possible to squeeze a little more power out of my 1987 Johnson 4hp 2-stroke (Model J4RDHCUD)? I used to have a late 80's Johnson 15 HP and read many times that the 9.9 and 15 were the same except for the carburetor. Is that the case with the 4hp? Would, say a 6hp carburetor fit it to increase the power a bit?

I have a 10 foot flat bottom and I top out at about 9.5mph, just shy of getting it to plane. I figure a little more power may get me there.

Thanks in advance for any help you can privde.
 
Just buy the 6hp. You’re getting 50% more power, I currently have 6 of them. The 6 has a much better starter assembly, twist throttle & are very robust, yet simple motors.
I run 14’ Jon boat, (flat bottom), & solo the 6 will plane it at 14mph.
 
Edchris177 said:
Just buy the 6hp. You’re getting 50% more power, I currently have 6 of them. The 6 has a much better starter assembly, twist throttle & are very robust, yet simple motors.
I run 14’ Jon boat, (flat bottom), & solo the 6 will plane it at 14mph.
Click to expand...
Thanks for the reply! I'll be on the lookout for a 6hp then. Seems the 4hp is about maxed out from the factory.
 
Back
Top