?RUNAWAY?

iivan q

Cadet
Joined
Dec 2, 2005
Messages
9
what does it take to runaway?<br />what serious damage occurs at high rpms?<br />pistons hit spark plugs,crank bearings gives?<br />the reason i ask is the shift rod is filed down at the neutral point.so if not careful it can start at WOT.<br />also while im here,a lot of oil/fuel/water<br />coming out of the little vents hole on the lower unit leaving a trail.<br />thanx in advance :eek:
 

iivan q

Cadet
Joined
Dec 2, 2005
Messages
9
Re: ?RUNAWAY?

hey,<br />its a 1971 25hp evenrude model#25102s,<br />im trying to temporaly hook up a tach to it<br />but i cant find an electric pulse for the send,<br />the guage is a teleflex standard,ing/ground/send.<br />anyone got a sight for this tach?<br />its a pull start as well as elect starter.<br />the only wires coming down off the points/mag<br />are the two black kill wires,<br />a got 12volts from batt to,starter/solenoid,i dont use the elect choke,and i have a push type starting switch and a seprate push type kill switch
 

G DANE

Commander
Joined
Nov 24, 2001
Messages
2,476
Re: ?RUNAWAY?

I had one with somewhat same problem. If it was killed in gear, it could occationally start at like 1/2 throttle. Nothing happened the couple of times it did so, both times when someone else than me opereated it. it just raced smoothly for a couple of seconds untill they realized they had to back off at the throttle of kill it by switch.
 

iivan q

Cadet
Joined
Dec 2, 2005
Messages
9
Re: ?RUNAWAY?

thanx for the reply.<br />yea the promblem here is that with the part filed down the motor does not know were neutral is, the armature plate has an advance arm that hits the shift rod ,when in gear it moves back and lets the thottle open but in neutral your only supposed to get maybe half thottle.<br />anyhow i would hate for one of the kids to overrun the motor,<br />i thought that a good article on the topic runaway would be interesting to read.
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: ?RUNAWAY?

depends on the engine. the old 40,35 and 33's had a vacum cutout switch that I learned the hardway not to bypass. some engine/carb designs are more prone to runaway than others but I can tell you once a mid-sixties 40 runsaway there is no good way to kill it and keep your skivvies clean.<br /> I saw a 55 suzuki runaway that tossed a rod out the block. my advice is to repair the safty sytems, they are there for a reason. the bearings dont like the hammer effect of high speed no load operation, sleeve bearings will tolerate it a bit better needles just dont like it.
 

iivan q

Cadet
Joined
Dec 2, 2005
Messages
9
Re: ?RUNAWAY?

thanx again,<br />i was able to thread the end of the shift rod and screw a butterfly nut down on top,<br />so when in neutral the nut now stops the plate from moving past its mark,<br />i took it to the lake this morning and did some tuning/fishing and motor seems like it should,<br />i dident even see that trail of fuel/water coming out of the lower unit vent holes i saw yesterday when i took it out of the test tank.<br />i still couldent figure out the tach so im not sure of my rpm but it sounds good :rolleyes:
 

itstippy

Chief Petty Officer
Joined
Jul 17, 2003
Messages
548
Re: ?RUNAWAY?

Best tach for those is a "Tiny Tach". You just wrap a wire a couple times around a spark plug wire and you get a reading every 2 seconds. They're disposable tachs with 5 year lithium batteries. Work great. Google "Tiny Tach".
 

Paul Moir

Admiral
Joined
Nov 5, 2002
Messages
6,847
Re: ?RUNAWAY?

If you have some electronics background, you can adapt a universal inboard/outboard tachometer. But you'll need to be able to construct it from scratch.
 
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