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70 HP Johson 2 Stroke Can go faster?

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nigelsalari

New member
I got an lightweight boat with an johson 70 HP 2 Stroke. But it only goes 50 KM/H I've seen videos where the go way faster are there any mods or other thong I van do to go faster?
The motor runs fine in the water on full trothle it does stutter sometimes but its probably the feul line that's dirty I ordered an New one
I wil post video en picture of the boat.


Screenshot_20230602_181354.jpg
 
3 thoughts:
Does it have the appropriate size propeller? What's the rpms at WOT?
Is the boat heavy? Waterlogged? Water in a "sealed" compartment?
Is the speed measurement accurate?
 
HumberJewel said:
3 thoughts:
Does it have the appropriate size propeller? What's the rpms at WOT?
Is the boat heavy? Waterlogged? Water in a "sealed" compartment?
Is the speed measurement accurate?
Click to expand...
I haven't got any idea if the propeller is the right size we bought an New one with the same numbers as the old one.
The boat is very light and I don't think it's watterlogged. How can I check to be sure?
For measurement I use my phone and GPS app
 
Looks like Europe is your location.-----What numbers are on the propeller ??-----Model # of the motor?----Compression values are ?----Does spark jump a gap of at least 8 mm on each lead ?-----Carburetors clean, including jet in bottom of float bowl ?----Flywheel key checked.-----This should not be hard to figure out with some inspection / testing !!!----
 
The propeller is an 13x1/4x17 its an New one.
Model of the motor is an Johnson J70EL CSA
We did an compression test they al 3 did 10 bar/145PSI.
The spark plugs spark fine.
We cleaned the carburetors and the jet in the bottom.
Never heard af an flywheel key check I wil do my research and test that.
 
I guess I have to repeat.----Does spark jump a gap of 8mm, yes or no ?----Sparkplugs have nothing to do with that test.
 
With a 17 p gear ratio of 1:2.4 you may get a little more out of it but not huge amount without way above the WOT range.. do you have a tachometer on the boat I have similar setup and get with 19 p and family onboard about 38mph 60kmh.

Like racer said good spark.
Good fuel delivery
As your compression is good
You checked timing think should be 19 for your motor but check before
 
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