Boat Runs Great, won't start after a ski run.
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=50813
Printed Date: November-22-2024 at 2:20pm
Topic: Boat Runs Great, won't start after a ski run.
Posted By: MrMcD
Subject: Boat Runs Great, won't start after a ski run.
Date Posted: August-04-2022 at 2:52pm
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I went out with some old friends yesterday to ski. 4 in the boat, ages 64 to 76. We all took 2 ski runs each. Most amazing the 76 year old had a knee replaced in April and has resumed water skiing and looked great out there. We did not use my Nautique this time. We were in a 1986 Mastercraft one of the other guys owns. After every ski run the boat would not want to start, ran great, pulls hard, has the Powerslot tranny. Asking him questions trying to help, no tools in his boat. It does have some kind of electronic Points replacement, Petronix? I did not look to see what type. His coil was no hotter than the manifold below it. It did not seem to matter if we pumped the gas or not. He said last time it did this he checked the plug wires, said when it has no spark it won't start and then suddenly it has spark again and starts. Trying to figure out where the issue is. His ballast resistor is removed. Seems to have 12V at the coil. Again, no tools so could not do much. He has replaced the key switch and mentioned it does have one extra pole that is only hot while the starter is engaged. Is this pole supposed to be hooked to a second wire that goes to the positive side of the coil? I think the second wire would trigger the starter solenoid and then go to the Coil to provide 12V while cranking? The boat cranks perfect when the key is turned so something is off it does not always start. Starts perfectly cold but no start after a ski run. Sometimes it does not start for 30 seconds, sometimes 5-10 minutes, then fires up and runs like brand new? When it starts, it starts like there was never a problem and instantly goes into a normal smooth idle and runs fine to ski. You do not have to rev it to clear our fuel, it just starts and purrs. I will try and help him fix it, just want to see if my thoughts are accurate as to the cause. I think this is a PCM engine, it looks like the standard 351 PCM but I did not really check. Manifolds etc looked just like my 78 Nautique PCM. I have the PCM wire harness diagram and Tim's nice diagram but I keep thinking about the one pole in the ignition switch without a wire attached that is only hot while the starter is cranking. Makes me wonder what is triggering the starter to turn, I have not seen a switch with 2 start poles on the back of the switch. Again, this information came from the owner, it needs to be verified. the boat ran fine for a season after the new switch was installed and then started acting up, according to the owner. This was my first ride in this boat so no history to share from me but the owners brother is a good friend and he told me the starting issue has gone on for a while now. Ski report, wake was nothing special, low but a little hard, boat tracked good. Water was perfect and flat for us so I did not get to enjoy the flat bottom Mastercraft thump on wakes. They all skied on 75 foot rope so I did that also. Have not done that in a while. Turns felt slow but it made you think about body position in the whole turn and pull. In short line it all happens much faster not much time to think. Thanks Mark
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Replies:
Posted By: Jonny Quest
Date Posted: August-04-2022 at 3:45pm
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McD: Responding to your question regarding key switch extra pole... With a Ford remote starter switch (sometimes referred to as the solenoid switch), on these older SBF engines, the "I" terminal on the switch is often energized when the key is in the "start" position. This was done to ensure that the coil received full voltage during engine cranking. The carb engines with an electronic choke can pull needed volts away to the choke and detrimentally impact the volts going to the coil. After the engine starts and the key is turned from "start" to "run" then the "I" terminal is no longer energized. This little trick form Ford would bypass the ballast resistor and give full volts to the coil during engine start. Once the engine is started, then the ballast resistor takes over with its usual function. KENO turned me on to this little tidbit. I've verified it on several older SBF engines. To throw an electric wrench into the wiring, PCM later used the "I" terminal differently with the ProTec engines. With the ProTec engines, the "I" terminal was wired to a 12 or 15 amp breaker and then the "I" terminal remained energized when the key was in the "run" position. This "I" terminal is what provide the 12V for the ProTec control module. If you can figure out the coil make/model, you can quickly determine if it requires a ballast resistor or not. A hot coil can be a b!tch to deal with. The symptoms you are describing could easily be attributed to coil problems. JQ ------------- Current 2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
Posted By: KENO
Date Posted: August-04-2022 at 8:07pm
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I guess I'm confused whether you're talking about the keyswitch on the dash or the slave solenoid on the back of the engine which Jonny is talking about.. 86 was the last year of the PCM engine for Mastercraft then they went to Indmar 351's in 87, so the TRB diagram would be good
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Posted By: MrMcD
Date Posted: August-04-2022 at 8:11pm
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Thanks JQ, I was aware of the second power supply for the start mode to the coil. Looking at the schematic it looked like PCM took that wire to the solenoid at the starter and then routed it to the coil as the back up starting 12V supply. In this boat he has one empty pole at the key switch that is 12V while cranking. I think the solution is to add one new wire and take it to the coil direct from this source. He does have 2 wires connected to the IGN Pole on the key switch right now and I was wondering if the second wire may be the second source going to the coil and he just connected it wrong. Again, with no tools at all we just lived with it yesterday but I want to help him eliminate that starting issue. His coil was no hotter than the surrounding surfaces, Intake manifold etc so I think the coil may be just fine. He had one ordered and was waiting for it yesterday but I really did not think that was the issue. Mark ------------- |
Posted By: MrMcD
Date Posted: August-04-2022 at 8:18pm
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I should have looked at the engine provider when we had the lid up yesterday, everything looked so familiar I just ASSUMED it is a PCM but I need to confirm. The extra pole is on the back of the Ignition Key switch and it is HOT 12V when the key is turned to the start position. He did put a new Starter in this same boat last year but I did not look at the wires going to the starter. I think it will be a simple fix if he adds the second 12V wire from the extra Ignition switch pole and runs it direct to the coil 12+. Odd that it starts well cold but not hot. And only takes a few minutes to cool off and work again. Maybe his distributor with the Pointless conversion is at fault but I would think that would also cause issues while operating under loads. Mark
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Posted By: MrMcD
Date Posted: August-04-2022 at 8:38pm
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I called Tony and confirmed it is a Pleasure Craft Marine 351W. The engine looked much newer than the boat to me so I suspect it was overhauled at some point recently. My buddy Tony has only had it for 4 years. I found this searching old posts and it may help correct the issue. MARINE BOAT WIRING Accessories You need to determine how your electrical system is wired. Some systems supply power to the gauges through the ignition circuit. Other systems will have seperate wires to power gauges that connects at the switch. If you have other accessories like a radio or depth/fish finders connected to a seperate fuse panel it may be powered through a seperate wire as well. Here is the marine standard color code for wiring. It depends on how old your boat is whether or not the code is used. Yellow or Blk- Ground Return, Negative Mains Lt. Blue- Oil Pressure Oil Pressure Sender to Gauge Dk. Blue- Cabin & Instrument Fuse or Switch to Lights Brown- Generator Armature Generator Armature to Regulator Alternator Charge Light Generator Terminal or Alternator Auxiliary Terminal to Regulator Pumps Fuse or Switch to Pumps Green- Bonding System Bonding Wires (if insulated) Grey- Navigation Lights Fuse or Switch to Lights Tachometer Tachometer Sender to Gauge Orange- Accessory Feed Ammeter to Alternator or Generator Output and Accessory Fuses or Switches Common Feed Distribution Panel to Accessory Switch Pink- Fuel Gauge Fuel Gauge Sender to Gauge Purple- Ignition Ignition Switch to Coil & Electrical Instrument Instrument Feed Distribution Panel Electrical Instruments Red- Main Power Feeds Positive Mains (particularly unfused) Yellow- Generator Field Generator to Regulator Field Terminal Brn w/Yellow- Bilge Blowers Fuse or Switch to Blower Yellow w/Red- Starting Circuit Starting Switch to Solenoid ------------- |
Posted By: KENO
Date Posted: August-04-2022 at 9:08pm
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It sounds to me like he has a keyswitch with an Accessory position. 1 click left from the OFF position. The Ign terminal will have the yellow/red wire only. It goes to the neutral safety switch, then to the starter if the switch is made up. The Start terminal will have 2 purple wires attached to it. One goes to the coil, choke and alternator excitation. It changes colors along the way as shown in the TRB diagram. The other one is the hot feed for the dash. The Batt terminal is 12 volts into the key from the battery/alternator. A 10 gauge red wire The Acc position would be for a radio etc that you want to power with the engine Off. Since you had no tools I'd verify what was said about the 4th terminal having power in Start. Assuming the 4th terminal is the Acc terminal it has power when the key is in the Acc position and the Run position but no power in the Start position (different from what you said or what he told you) If it starts good cold but nor hot, before you get screwing around with wiring or anything else, I'd let his new coil show up and install it and see if the problem goes away .
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Posted By: MrMcD
Date Posted: August-04-2022 at 9:17pm
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That is the plan, I just talked with him and his coil came in. You might have nailed it but the coil looked good, no oozing fluid, was not running hot. I did not confirm anything he told me so information may not be perfect but I think we are on the correct path. The part that still had me thinking the coil was OK was how good it ran no matter how hard we ran it. It just does not want to fire up hot. Now for the next question, did he order the correct coil or not? I will report what fixes it.
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Posted By: steve600
Date Posted: August-11-2022 at 7:44am
| Some trouble on hot restarts are caused by a dirty needle and seat allowing fuel to drip into the primary on the carb. It will start good cold as this fuel will have time to evaporate. |
Posted By: KENO
Date Posted: August-11-2022 at 6:28pm
According to the quote below from the first post, it's got no spark when it doesn't want to start
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steve600 wrote:Posted By: MrMcD
Date Posted: August-12-2022 at 1:55am
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We had planned to go out again Wednesday but that fell through. He has not had it back on the water yet but I believe the new coil is not installed. I will update once it goes out again. ------------- |
Posted By: MrMcD
Date Posted: August-25-2022 at 1:35pm
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Can’t offer a final on this issue yet. The owner has not been able to take the boat out since the last outing. He installed the new coil but has not changed the wiring. We did ski yesterday but used my boat due to logistics. ------------- |