175hp,johnson o/b blows 20a fuse by the starter

[luv2fish13]

engine ran fine several days ago. now the 20a fuse by the starter, on the port side of the motor blows as soon as the battery selecter is turned on, the only thing i've done since running it last, was to remove an old micrologic explorer loran unit. any help will be greatly appreciated

 

[mn808gade]

Re: 175hp,johnson o/b blows 20a fuse by the starter

depending on year--- ck ALL trim switches(none accdently pushed?)boat switch???,... disconect large red plug (control box harnass) now see if fuse blows. btw- use long 20amp fuses,visible&cheaper.

 

[mn808gade]

Re: 175hp,johnson o/b blows 20a fuse by the starter

recheck your last job(b4 fuses starting blowing),pinched wire?

 

[emdsapmgr]

Re: 175hp,johnson o/b blows 20a fuse by the starter

Some good comments. Check the key switch in the control box. It is designed to start the engine. (also to feed power to the dash tach-only.) Many folks open up the box and run + and - wires to the dash for the radio, gauges, etc. That 20 amp fuse is not designed to run a bunch of other electronics-rather to be dedicated to the engine only. All dash electronics on newer boats are fused, then tied into a single buss which is wired direct to the starting battery on a single high amp fuse.

 

[luv2fish13]

Re: 175hp,johnson o/b blows 20a fuse by the starter

hey guys, i checked area where i removed old loran, all looks good.when i disconnected the large red plug for the control box, the short went away,and all accessories still functioned, even the tilt switch. is the next step to dig into the control box?, i just got this boat, and did notice the dash tach doesn't work, could this cause a short? one more thing i read somewhere, could the choke solenoid be stuck? how would i check that. tx.

 

[emdsapmgr]

Re: 175hp,johnson o/b blows 20a fuse by the starter

That's a good test. The tilt switch on the throttle handle plugs in separatedly and does not go throught that red plug. Indicates a problem somewhere in the control box or wiring to that red plug. Have a look at the key switch. They can be a problem, esp if they get rainwater in them. You can pull that purple wire off the choke solenoid and see if it makes a difference-they are not prone to short out.
The tach gets it's signal from the rectifier/regulator (charging system) at the engine. If the battery charging system appears to be working, (check the volts on the voltmeter) that R/Reg. is probably sending a signal to the tach.

 

[luv2fish13]

Re: 175hp,johnson o/b blows 20a fuse by the starter

thanks for the info, any tips on how to test my ignition switch

 

[emdsapmgr]

Re: 175hp,johnson o/b blows 20a fuse by the starter

I'd use a simple household type voltmeter that can also do continuity. Helps to have a factory original service manual-they have wiring diagrams in them.

 

[luv2fish13]

Re: 175hp,johnson o/b blows 20a fuse by the starter

the ignition switch checks out fine, any ideas what to try next???

 

[emdsapmgr]

Re: 175hp,johnson o/b blows 20a fuse by the starter

I'd probably look for a bad/grounded/shorted wire in the loom. Do some continuity tests from the switch to the red plug.

 

[luv2fish13]

Re: 175hp,johnson o/b blows 20a fuse by the starter

with the red plug disconnected, i found a short between the the red/purple(battery) to ground, i disconnected the red/purple wire from the ignition switch, and there is a short to ground on that end also, i guess the wiring harness is damaged, i can see no visible damage, 2 questions what could cause this?, and where's a good place to order a new wiring harness, couldn't find it on here, thanks for all your help with problem!!!

 

[emdsapmgr]

Re: 175hp,johnson o/b blows 20a fuse by the starter

Hard to say just what the root cause of the problem is. You don't mention what year engine you have. If you check this web site: epc.brp.com, you will find all the parts lists for the various years of OMC/Bomardier engines. I did a quick check on an 89 harness (one of the engines which still used the red plug) and found that 393129 wire harness was discontinued. (Last time it was made it was about $120. Probably most of these harnesses have been discontinued for these older crossflows. In this case, however, there appear to be 3 Bombardier dealers here in the U.S. that have one of these harnesses in stock as new. Once you have identified the specific year of your engine and found the harness you need, see any Bombardier dealer and ask them to use their internal network to other dealers' stock availability on the part number you need. Another alternative. Most of these harnesses are 20 feet long-usually way more than you typically need. If you did some electrical test probing you might find where the shorts are. Always possible to cut a huge chunk defective of harness out and carefully splice it back into working order.