? on I/O spark plugs for trolling

[paulywood]

I started trolling with my boat last year. It has a 175 horse 4.3 V6 I/O. I read somewhere that it's better to have hotter burning spark plugs when trolling so the plugs don't load up and foul. Does anyone have any suggestions on what plug and brand? Does it matter what wires I put in? Plan on replacing both as soon as I pull the boat out, hopefully in the next 2 weeks. Thanks.
Nick

[SalmonBum]

I have always run the std plug, hotness wise. Change them every spring, after you run the motor for a trip. While you are changing the wires, do the cap/rotor. make sure to get marine grade.

[lkmifisherman]

If your carb is dialed in right your boat will troll all day and not foul any plugs using the standard plugs....And as SalmonBum said USE MARINE parts...One small spark and some fuel vapors will make one big boom...Most any reputable parts store will have what you need...


LMF :fish:

[FishTales]

:yeahthat: I have the same engine in a '86 Crestliner and I can troll all day with standard plugs.
Rich

[Priority1]

If your rig still uses the old breaker points consider upgrading to electronic ignition. This will make a world of difference.:) I upgraded mine last year, and noticed the difference in performance and economy.

[paulywood]

The problem is that the carb is jetted for speed. It's not set up to troll. I never had any problems last year I was just trying stop one from happening. "While you are changing the wires, do the cap/rotor" I just had this done last year. And it's easier said than done. They had to remove the wood frame around the engine to pull the rotor. If anyone else has any "usefull" advice on "spark plugs" I would appreciate it.

[SalmonBum]

Running a hotter plug may help with fouling, but you increase your chances of putting a hole in the piston. If I were you, I would run the boat with the std plug before you go running hotter, since you may not foul any at all (u never said if you fouled any in the past). IF you do start throwing plugs and you plan on using the boat for trolling, I would recommend adjusting the carb for that type of use, rather than taking the cheap way out and going with different temp plugs. As for wires, I don't believe changing to a different type (thickness) wire will help you in your case. I would go with a Good quality MARINE grade set of wires. That is a real bummer about the Cap/rotor. Even with marine parts, those things need to be inspected/replaced every yr or two. Don't overlook it just because it’s a "pain" to get to. Preventative maintenance is when helps you from getting towed in. I have 15(4 days a week avg.) yrs on the Big water, have yet to be towed in.

[SalmonBum]

BTW, switching to electronic ignition is a great investment. BUT…. if that 4.3 of yours is an older OMC, you CANNOT use the $100 upgrade kit. The OMC uses an Electric Neutral shift switch, which basically kills the motor for a millisecond when switching between F\N\R. If you install it, the motor will “die” as it’s suppose to, but will not start back up. You could remove the switch and set the idle lower, but I wouldn’t recommend it. The motor does that to save wear and tear on the drive. If you have a Merc, forget everything above and go buy the kit. Money well spent.

[Priority1]

Salmon Bum is correct on the OMC issue, but there is a way to deal with it. Pertronics Ignitor put this fix out there using some inexpensive Radio Shack parts. Check the link below
http://www.pertronix.com/tech_support/assets/diodefix.pdf

[FERG 06]

I started trolling with my boat last year. It has a 175 horse 4.3 V6 I/O. I read somewhere that it's better to have hotter burning spark plugs when trolling so the plugs don't load up and foul. Does anyone have any suggestions on what plug and brand? Does it matter what wires I put in? Plan on replacing both as soon as I pull the boat out, hopefully in the next 2 weeks. Thanks.
Nick
Got some good info today from the dealer on my out board fouling out the plugs. If the thermostat is not holding the water up to the right temp the engine will be running cold and foul the plugs even though I'm running hotter plugs. He said if I can hold my hand on the engine it's too cold. On your I/O it might have a temp rating on the thermostat in which case you can double check it by putting it in a pan of water with a thermometer and heat it up watching to see when it opens up. Hope this helps.
By the way, running hotter plugs won't put holes in pistons. Hotter plugs merely hold on to their heat longer before transfering it to the head. They do not spark hotter! The only way to put holes in pistons, (beside with a hammer) is to have pre-ignition or detenation in the cylinder. This is usually from a timing problem or lower octane fuel than your engine calls for, causing the fuel to ignite before the plug fires.

THINGS TO DO TODAY: 1) Get up, 2) Survive, 3) Go to Bed.

[Priority1]

One other pluss to running Electronic ignition, and a hotter coil is, you can gap the plugs a lil wider. I went up from .035 to .043 on mine. It starts and runs a lot better.:)

[roger23]

http://www.championsparkplugs.com/characteristicImages/7_t.jpg
(javascript:popImage(7);)
http://www.championsparkplugs.com/characteristicImages/8_t.jpg
Heat ranges are not the same between brands
(javascript:popImage(8);)
Heat range

The term spark plug heat range refers to the speed with which the plug can transfer heat from the combustion chamber to the engine head. Whether the plug is to be installed in a boat, lawnmower or racecar, it has been found the optimum combustion chamber temperature for gasoline engines is between 500°C–850°C. When it is within that range it is cool enough to avoid pre-ignition (javascript:glos('Pre%2Dignition','2','1')) and plug tip overheating (which can cause engine damage), while still hot enough to burn off combustion deposits which cause fouling (javascript:glos('Fouling','2','1')).

The spark plug can help maintain the optimum combustion chamber temperature. The primary method used to do this is by altering the internal length of the core nose, in addition, the alloy compositions in the electrodes can be changed. This means you may not be able to visually tell a difference between heat ranges. When a spark plug is referred to as a “cold plug”, it is one that transfers heat rapidly from the firing tip into the engine head, which keeps the firing tip cooler. A “hot plug” has a much slower rate of heat transfer, which keeps the firing tip hotter.

An unaltered engine will run within the optimum operating range straight from the manufacturer, but if you make modifications such as a turbo, supercharger, increase compression, timing (javascript:charglos('Timing')) changes, use of alternate racing fuels, or sustained use of nitrous (javascript:charglos('Nitrous')) oxide, these can alter the plug tip temperature and may necessitate a colder plug. A rule of thumb is, one heat range colder per modification or one heat range colder for every 75–100hp you increase. In identical spark plug types, the difference from one full heat range to the next is the ability to remove 70°C to 100°C from the combustion chamber.

The heat range numbers used by spark plug manufacturers are not universal, by that we mean, a 10 heat range in Champion is not the same as a 10 heat range in NGK nor the same in Autolite. Some manufacturers numbering systems are opposite the other, for domestic manufacturers (Champion, Autolite, Splitfire), the higher the number, the hotter the plug. For Japanese manufacturers (NGK, Denso), the higher the number, the colder the plug.

Do not make spark plug changes at the same time as another engine modification such as injection, carburetion or timing (javascript:charglos('Timing')) changes as in the event of poor results, it can lead to misleading and inaccurate conclusions (an exception would be when the alternate plugs came as part of a single precalibrated upgrade kit). When making spark plug heat range changes, it is better to err on the side of too cold a plug. The worst thing that can happen from too cold a plug is a fouled spark plug, too hot a spark plug can cause severe engine damage