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View Full Version : Starting problem when engine is warm with a 1984 S&S


keith3613
07-27-2010, 11:44 AM
My 1984 S&S starts fine when it is cold. When it warms up, an extra shot of gas is needed to help it start. Once started, it runs fine. The timing, dwell, spark plugs, plug wires, carburetor, points and distributor are fine. Im thinking the coil may be the culprit. Perhaps converting to electronic ignition is the answer. Anyone seen this problem before?

oldairboater
07-27-2010, 12:37 PM
Extra shot of gas? Does that mean you work the accelerator pump one time by pumping the throttle? If it is the accelerator pump method--so what---boat starts. Convert to electronic ignition anyway. Points are old technology and they can be a pain in the butt. I do not miss points. I could always get points to fire enough in the past to get me home but they were a constant wear item that seemed to always need attention at the most inopportune time.

keith3613
07-27-2010, 12:41 PM
What I means is, the engine used to start with a bump of the switch. Now, and only when it is hot, do you have to give it some gas (throttle) to start.

thatsmrmastercraft
07-27-2010, 12:47 PM
What condition are the plugs, points, distributor cap & rotor in?

keith3613
07-27-2010, 01:43 PM
All of the ignition parts are in excellent condition. The problem just started last week. My first reaction was to suspect the coil. It's the original coil. However, I didn't want to change the coil because I was thinking about installing electronic ignition. It just strikes me as strange that it starts easily when cold, but is hard starting after it's warm. The boat runs great after starting.

oldairboater
07-27-2010, 04:28 PM
Not always but usually if a coil starts breaking down they misfire or quit. I would have ignored this as long as the boat starts and idles down to the right rpm while running like a scalded cat wot. Sometimes when you hunt a problem you can create more problems so I like to make sure I am fixing a problem not creating or confusing problems. I would still change to electronic ignition and see if that solves the problem since you want to change anyway.

helton333
07-27-2010, 04:33 PM
I had similar problems and replaced all (rotor, cap, went to E.I.) - once we replaced the coil - it ran "hot" again. inexpensive and quick to try and solve that way first.

thatsmrmastercraft
07-27-2010, 05:02 PM
I'm not normally one to throw parts at a problem, however, you can't go wrong with replacing a 26 year old coil.

jdubwall
07-30-2010, 08:25 AM
Put the ELECTRONIC Ign. in it........ That will take care of your prob..... My brother used to own a 1985 supra and it had the same issue, after putting the elec. ign. in it, and tunning the carbs. slightly it ran perfect... hope this helps :)

keith3613
08-01-2010, 10:43 AM
I installed a Petronix marine model 1581 Ignitor electronic ignition conversion with a matching Petronix Flame Thrower Coil model 40111. All problems have been solved. The installation is simple. You remove you old points plate (2 screws). Install the Petronix plate (2 screws). Remove your old coil and install the Petronix coil. All of the wires hook up the same. Hook up the two wires from the Petronix conversion to the new coil (red to plus black to minus). Note, the old ballast resistor at the back of the engine is no longer needed with the new Petronix coil. The new coil has a ballast resistor built in it. Simply remove one of the wires from your old ballast resistor on the back of the engine and attach it to the other post of the old ballast resistor. This effectively connects both wires of the old ballast resistor together or eliminates the old ballast resistor. Note, you must set the distributor timing with a timing light when you’re done. My distributor timing was a mile off after installation and the engine wouldn’t idle under 2000 rpm’s. I had to turn my distributor clock-wise about 1/8 of a turn to find the timing mark. The parts were purchased from Car Shop Inc. One other note, it’s best to buy the matching coil with the Petronix ignition conversion for best results.

http://pertronix.carshopinc.com/product_info.php/products_id/77/1581
http://pertronix.carshopinc.com/product_info.php/products_id/49/40111

keith3613
08-15-2010, 08:57 PM
I’d like to give some additional information about my hard starting issues. Occasionally, the boat still doesn't seem to start easily. The only thing left to investigate was the carburetor mixture. I contacted the guy who rebuilt it 2 years ago. His instructions were to search for a vacuum leak by spraying carburetor cleaner around the base of the carburetor. Plus, spray the cleaner near any suspected leak areas. After that, he suggested to remove, clean, replace and readjust (begin 1 turns out) both idle mixture screws. Plus, spray the idle mixture screw holes with carburetor cleaner. None of those things seemed to help. Therefore, after setting the mixture screws to best idle, I continued to open the screws equally and start the engine. As the screws were opened, about a half turn at a time, the engine got easier to start. When the screws were opened about 2 turns, the engine started like it used to. I remember when the rebuild was done the rebuilder commented that the carburetor was set very rich. Looking back, I bet this was done to aid in starting the engine. It’s something to try if you’re setting an old Holley 600 on a 1984 Starts and Stripes.