Suzuki DT65 Electrical Issue

tmas suzuki

Cadet
Joined
Nov 20, 2012
Messages
14
Hey guys,
Well i'm new to the forum and new to outboards. I've just bought my first boat. It has a 1979 Suzuki DT65 on it. Motor was sort of a wreck when I bought it. I had to put an ignition switch in, and the PO just had all the wires cut and hanging, so I had to chase each back to where they came from, and I used the wiring diagram that came on the igntion switch. After rebuilding the Carb and fuel pump, I hooked up the battery and tried her out.
Engine fired up after 10 seconds on the starter, whew! I lucked out.

Went to the marina and put her in the water. She fired right up again. First thing I checked was that I was getting water out of the little hole it's supposed to. It's not a steady hose stream, but a good amount of water was coming out so I figured the impeller was good enough for a test run. Warmed her up and started chugging out of the marina. Got out of the no wake zone without a hitch. Pushed the throttle down slowly and off we went. She ran strong and came right onto plane.
After a couple minutes I shut her down and did a little fishing. Decided to head in and pushed in the choke to start it, didn't hear the click. So I turned the Key...NOTHING. Oh great I thought I was stranded a mile out. Pulled the motor cover and started prodding around looking for a loose wire or something. Found the rubber fuse holder clamped on the port side, and sure enough, there was a 25AMP fuse in there...popped. I had ONE extra fuse in the boat. Started her up and took off again...left her running, went and got my truck and backed in. Boat had died while idling, and the fuse popped again! I figured I'd be OK to hard wire it past the fuse just to get her back on the trailer. It worked long enough to get it onto land. I pulled the motor cover, and the 30 seconds I ran it the wire had started to MELT. Oh boy.
I wired the fuse back in and ran it when I got home. Took it back out with a bunch of extra fuses, and sometimes the fuse pops and other times it doesnt??????? :facepalm: Now what?
What would you guys recommend I check? It seems like getting the boat up into full throttle range is what might be causing the fuse to pop, but not every time. AND the motor doesn't die after the fuse pops, I can run it fine, it just won't start again. ANY help would be great! Is it possible that I have a wire wrong on my ignition switch?
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
8,912
Re: Suzuki DT65 Electrical Issue

Sounds like you have something shorting out,
bad insulation/pinched wire/ grounding out?
 

tmas suzuki

Cadet
Joined
Nov 20, 2012
Messages
14
Re: Suzuki DT65 Electrical Issue

thanks 99yam, I've looked that wire over really close and can't find any shorts, kinks, or even brittle wire. I'm trying to find a wiring diagram to find out if there is another wire connecting to that one somewhere that could be causing a short.
 

madwelder1971

Recruit
Joined
Nov 12, 2012
Messages
4
Re: Suzuki DT65 Electrical Issue

i have dt65 1978 went out fishing came back flushed it turned it off went to start it no spark
i think it could be the switch on yours on the side of the engine for the gear select
still cant find what wires are what have you sorted it yet thanks andy
 

tmas suzuki

Cadet
Joined
Nov 20, 2012
Messages
14
Re: Suzuki DT65 Electrical Issue

I have searched this wire up and down and didn't find anything suspicious of a short.
Here is the weird thing. After much experimenting today trying to figure what causes the short, I am under convincing evidence that it only shorts when engine reaches high RPM for several seconds or more. I putted around at half throttle making many turns and coukdnt get it to short, but every time I got into the throttle it wound up blowing the fuse. Maybe its just a coincidence, but I tried it several times.
Any more ideas would be great, thanks guys I'm left scratching my head on this one.
 

stylesabu

Master Chief Petty Officer
Joined
Aug 2, 2009
Messages
849
Re: Suzuki DT65 Electrical Issue

try full throttle with engine off.turn key on just don't start motor if it pops fuse problem is in control box. be very careful if you take box apart,many small pieces and everything must go back together correctly. yhere is a possiblity that something in the box is shorting out.
 

tmas suzuki

Cadet
Joined
Nov 20, 2012
Messages
14
Re: Suzuki DT65 Electrical Issue

OK, here's a question. I decided to ask on this thread before I start a new thread. The fuse only pops at higher rpms for several minutes. I've decided that it makes sense to me that my magneto assembly could possibly be putting out too high of AMPERAGE at higher rpm. Any ideas how to go about testing this theory??? ALSO, what part on the motor, if any, "regulates" the output from the magneto. I know there is a coil in the stator assembly that goes to battery charging, and there is a rectifier that connects to my main wire as well. Could a bad Rectifier or charging coil be causing too high of amperage to be travelling through this wire? thanks again for any ideas or help!
 

madwelder1971

Recruit
Joined
Nov 12, 2012
Messages
4
Re: Suzuki DT65 Electrical Issue

OK, here's a question. I decided to ask on this thread before I start a new thread. The fuse only pops at higher rpms for several minutes. I've decided that it makes sense to me that my magneto assembly could possibly be putting out too high of AMPERAGE at higher rpm. Any ideas how to go about testing this theory??? ALSO, what part on the motor, if any, "regulates" the output from the magneto. I know there is a coil in the stator assembly that goes to battery charging, and there is a rectifier that connects to my main wire as well. Could a bad Rectifier or charging coil be causing too high of amperage to be travelling through this wire? thanks again for any ideas or help!

i would change the regulater/rectifer because it turns it from ac to dc +they are cheap i put one on my old yamaha for a motor bike off ebay cost me ?20 worked spot on allso check the fuse holder i have a evinrude 70 which kept blowing the trim fuse it was a faulty fuse holder hope this helps
andy
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
8,912
Re: Suzuki DT65 Electrical Issue

The motor will not put out very much current(amps) at low RPM, but will put out to spec at high RPM.

You can measure the Ohms and the peak voltage out of stater to make sure they are in spec
Also the voltage out of rectifier/regulator

Never heard of them putting out too many amps, maybe too much voltage
 
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