Print Page | Close Window

8v input at ballast resistor

Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=50852
Printed Date: November-22-2024 at 2:25pm


Topic: 8v input at ballast resistor
Posted By: MechGaT
Subject: 8v input at ballast resistor
Date Posted: August-20-2022 at 10:19am
I am looking into an issue with my boat not running great, it runs fine for a bit then acts like it lost some cylinders. I started testing voltages and the high side of the ballast resistor was 8V or a little over, low side was 4.5V. I checked voltage at the solenoid and breaker back there and get 12.5V. Unplugged the Mallory distributor (Skidim conversion kit for Protec) & voltage went up to 12.2. Is this normal? I am sniffing in the right area?

-------------
'92 Sport Nautique


Replies:
Posted By: MechGaT
Date Posted: August-20-2022 at 11:05am
I just fired th boat up and with it running the voltage on the breaker was 14.2v. The high side of the resistor was 11.3V and the low side was 8V. Those look right to me. Afterward the voltage was back where it was before.

Other, probably related, thing is that I couldn’t get the idle below about 1200 rpm. I was messing with the curb idle screw and it fired up running around 1400 or 1600. I backed it down, but it wouldn’t go below 1200.

-------------
'92 Sport Nautique

Posted By: desertskier
Date Posted: August-20-2022 at 11:19am
I don't know if it's causing your problem or not but you are losing voltage, ~3V, somewhere.  Probably through the dash.  You should read battery voltage at the input to the resistor.

-------------
92 SN - Owned since 93
99 Pro Air
89 SN - Went to live on a lake in Texas
75 Donzi 16 - Sold in 93

Posted By: MechGaT
Date Posted: August-20-2022 at 7:40pm
OK, thanks. That tells me I do need to focus on that more. I found a general wiring diagram that I printed off. It looks like there are a couple of differences in the wiring. It doesn't give me any clues where to start. I was thinking the issue could be in the distributor electronics since it went to the correct voltage when I unplugged the power to the electronic ignition module. Any thoughts?

-------------
'92 Sport Nautique

Posted By: desertskier
Date Posted: August-20-2022 at 8:10pm
When you disconnected the distributor the load was removed so the current draw went down or to zero.  If there is no or low current flowing through the circuit then there won't be any IR voltage losses and the voltage should go up at the resistor.  So it may or may not be a problem with the module but it sounds like you have a wiring problem either way.

Basically the ignition circuit starts at the battery then goes to the ignition breaker on the dash then through the dash wiring to the key switch then through the wiring harness to the 12.5A breaker on the engine.  Sounds like you have the skidim harness so I'm not sure how that is wired but there is probably a direct path from the output of the 12.5 breaker to the resistor.

I would measure the voltage at the 12.5 breaker.  If it is low there then measure at the key switch.  Then the ignition breaker.

Electronic components don't like low operating voltage.  It causes intermittent problems or failures.


Edit: The choke will draw some current also.  You can try disconnecting and see what the voltage does.


-------------
92 SN - Owned since 93
99 Pro Air
89 SN - Went to live on a lake in Texas
75 Donzi 16 - Sold in 93

Posted By: MechGaT
Date Posted: August-22-2022 at 5:07am
That makes sense, I stopped the current flow when I disconnected the distributor so the voltage went up. I don’t recall if the choke was hooked up when I did that, I unhook it because the run position seems to open it too fast. I will do more testing when I get a chance.

-------------
'92 Sport Nautique

Posted By: MechGaT
Date Posted: October-02-2022 at 8:55pm
I did some rewiring, increased the wire size going to the ignition switch with better connectors and took the clock out of that loop. Voltage went up to 10.52 V. I also ran into an issue where the idle wouldn't decrease below 1,200 rpm. I thought perhaps the floats were adjusted incorrectly, since I did some checking on the carb to see if there was an internal issue. With the carb off the intake I noticed gas inside. I adjusted the floats, put it back on and got it running again and the rpm's started climbing. The warmer it got, the faster it got until it got up to 1800. The curb idle screw had no effect and I finally shut if off. I noticed gas on the secondary throttle blades. I went ahead and pulled the carb off again, thinking it must be a carb issue, possibly a rebuild needed. I then wondered if it could be a high fuel pressure issue. I'm thinking the next step is to test the fuel pressure. Any thoughts or guidance would be appreciated.

-------------
'92 Sport Nautique

Posted By: KENO
Date Posted: October-03-2022 at 7:32am
I doubt that your fuel pressure just decided to jump up for no reason.

High pressure would probably cause the engine to flood and not want to idle without stalling.

As a start, I'd probably pull the carburetor back off and check that the secondaries (and primaries) are closing all the way and then when it's back on the engine make sure the throttle cable is adjusted right .

Posted By: MechGaT
Date Posted: October-03-2022 at 1:55pm
Thanks for the help. Here’s a little more about what I have done. The last time I pulled it off I adjusted the secondaries per the instructions in the rebuild kit I had from a few years ago. I backed the screw out until it just touched, then I screwed it in one half turn. The primary side I set no more than square on the transfer slots. When running, the curb idle screw wouldn’t reduce rpm’s, but it would increase them. Also, I took the linkage loose while running it to see if that would make a difference. It didn’t.

I have had the bowls off 3-4 times this season and taken the metering block and metering plate off at least once each along with removing the power valve from the metering block. Do you think it could be an internal leak and just needs gaskets?

-------------
'92 Sport Nautique

Posted By: Gary S
Date Posted: October-03-2022 at 2:06pm
I would disconnect the throttle cable at the carb before I did anything else, then check the idle. You may not have got the carb back in the exact same spot on the spacer and are at the limit of the return in the cable. 

-------------
http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS
95 Nautique Super Sport


Print Page | Close Window