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Evo Engine on Airboat

chuckitt

Member
Hello, I'm new to the site and this is my first post. I built an airboat with the
Evolution engine for power. My problem is the vibration. Can this engine be
tuned to eliminate most of the vibration? I installed a fluid balancer on the
crank at the 3 inch sproket and it helped some. We are using the HI-4 ign.
I tried to post some pictures in the gallery and failed. I will try again.
Thanks, Chuck
 

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Kind of hard to tune the vibes out on 4" pistons. It looks as if you have some mounts to isolate the vibes but a full cushion mount like those found in cars may help but would have to be fabricated.

A ONE bladed prop??? Talk about vibrations :D
 
Thanks glider. That picture was taken before we had all the blades put on. The rubber
mounts are hard rubber that we use on big engines. I plan putting some soft ones on tomorrow
and weld in some gussets on the mount plates. I have built airboats with engines from
the 35 HP briggs up to the 572 big block chevy. We just haven't had an engine shake
this much and thought someone might have tuned one or done something to eliminate
most of the shake. Thanks, Chuck
 
it's a harley = it vibrates the hell out of everything the only reason you dont feel it on the newer dressers is the rubber isolation mounts they use the engines still vibrate...

on another note harleys belong in bike frames it's just wrong on so many lvl's lol
 
I put a VW on a rubber raft an drove it in the rapids at Kernville Ca. when I
was on Junk Yard Wars. Now we are building the mini airboats using the Briggs
35 HP and the Kohler 40 HP and making them run on dry ground. They are
V-Twins and they are the hottest selling airboat today. We have many
customers that own Harley's and some of them said if we make the EVOPRO
work, they will buy one. The EVOPRO just took first place in the FAA Airboat
Show at Wildwood FL.. I just thought there might be a guru on this sight that
had done something to eliminate most of the shake. We have put a fluid
balancer on the crank and changed the prop to a heavy wooden prop. Today
we are going to change the motor mount rubbers to soft rubbers and install
a fluid balancer on the prop shaft and see if that helps. I thought there might
be something we could do with the tuning of the engine to help.
We have video's on Youtube.com that show our mini airboats running. To
see them, in the search, type in mini airboat. If they perform that good with
40 HP, how good would it do with the 80 HP EVO?
 

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You may consider the TC88 B motor with the balancers in it like from a softail. They shake just a bit but nothing compared to the evo.
 
Thanks glider, I will check the specs on it if i can't make the EVO work.
Chuck

Here are new pictures as of this morning. Chuck
 

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Ever try those blue vibration idolaters on top of the mount stud also with a large area washer to kill some vibes? With the lock nuts on there it should help but as it is the vibrations are being transmitted with the washer on top through the stud and into the boat.

Looks like you finally added another blade to the prop. :D
 
Yeah glider, we have the rubbers on the bottom of the bolt also. I have some soft
black rubbers i'm putting on now. I just noticed the pipe on the # one cylinder is running
lean. I have to learn how to set up the FireBall HI-4 single fire ignition that we installed
of would the stock ign be better?
Thanks, Chuck
 
Nothing wrong with the stock ignition on the evo.

What I meant is an isolator on top and bottom of the engine case on the stud, like directly below the locknut
 
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