Eight years ago I change the points over to electronic ingation distrubtor, coil, and wires all new at that time. Problem is that the motor now seems to run a little rich. This spring I changed over to AC-MR44T instead of an Autolite 145 spark plug. I now have have problems with the boat not wanting to idle after it has been run low speeds while trolling for 4 or 5 hours. The Autolite plugs seem to work the best. The problem is I have no clue what the sparkplug gap should be since the conversion. A mechanic this weekend sugested I used a wider gap for the plugs this would cause them to burn hotter and which would elimanate the tendency load up while trolling. The current sparkplug gap is .035 the orginal gap prior to converting the electronic ignation he sugested that I regap them to .045. Any thoughts or ideas.

Ok, on the Mercruiser V8s of the 80s and up to 1995 they used MR43T spark plugs and they gap at .035.

I'm not sure ingation is a word, but it does come up on Google in a few places.

My thoughts on the running rich issue . . .

Play with timing, and if possible carb mixture setting.

Like this:

http://www.videosift.com/video/Dirty-Dancing-The-Corneringation-of-Baby

If it has been 8 years since the other ignition parts were changed you probably need a new cap and rotor at the least.

Also, if you are trolling at idle for several hours at a time all fluids in the engine and drive should be changed twice as often and gimbal bearing should be lubed every 50 hours or less.

I would also use a top cylinder cleaner,(the kind you run through the intake and choke the motor with), since you undoubtedly have carbon build-up. This may be preventing your valves from seating correctly. Idleing is hard use of your motor. You will need to give it extra maintenance.

That is a long time to have the boat engine idling, trolling is hard on an engine big enough to power a boat. Might be time to think about taking up a collection for an electric trolling setup.

Regarding the spark plug gap, that depends on what type of igniton was installed. If it was just an electronic trigger and no real spark boost (like CD or HEI) then the standard spark plug gap should be used. A wider gap stresses the other parts as well like older wires and cap, and can cause cross firing and other issues. Your "new" problem could be as simple as spark plugs but could also point to the other items like cap and rotor that have been mentioned. It could also be a gasoline formula issue.

If you have fishing buddies that go out with you I would work on getting an electric setup funded thru a joint venture.

vowel movement alert, vowel movement alert!

Thanks for the ideas. Changing the sparkplugs seems to be the place to start. The problem developed after I changed the plugs this spring. I am going to put a new set of Autolite plugs in. The Cap and rotor probally should be changed will be with in the next 2 weeks. I to not know the make diatrubutor was installed when the marina did the conversion 8 years ago. I will try to find part numbers on the cap and rotor. The boat is a 26 foot Pacemaker 305 cubic inch engine with a direct drive borgwarner 1:1. I admit that trolling is hard on the engine but according to Crusader Marine it should not hurt it. I have given a lot of thought to an electric trolling motor but there is no way to install one at this time. Another reason for a swim platform.

Thr trolling will not hurt the engine. If you are running #44 plugs, go to a step hotter, MR45T's, to try to burn off/prevent fouling deposit build-up.

long-term idling does not get the spark plugs very hot, and the 44's are the standard, middle of the heat-range plug.

You also should re-adjust your carburetor idle mixtures (assuming you are not F.I.)
Your idle mixtures should not be so rich as to foul the plugs, period, no matter how long you idle arround.

I have no idling issues (no, I do not idle for hours at a time, but often 15 or 20 minuites in some marinas) and I am running a step COLDER than middle (R43TS) plugs in my 454 (due to Nitrous Oxide usage).
My TS's are extended tips, which MIGHT help some as well.

The Autolites you HAD been running, may have been a step hotter, and you may have accidentally gone backwards in the conversion.

The advice to tune the rest of the system up as well is sound also.

Lowrider The Autolites were 145 which is equal to 44T. I also had them gapped a little wider 42 which probally helped. The boat did not run rich until I change plugs. I found my old log book with when and what I did. I have been hunting for it for 3 weeks. My old logs have help me more than once out of a jam Thanks everyone for the assist.

How long do the plugs last and what shape are they in. I can remember changing my 72 Comet w/302 to a Hayes MagnaPulse ignition. They did not mention about the need to change gap. My first set of plug lasted only a few thousand miles and burned up. Went from .035 to .055 and greatly improved things.

The plugs are not in bad shape. They were what you would expect out of a well tuned engine. I change plugs every 2 years as part of spring maintance. I beleive I gapped the AC wrong to narrow and that the gap should have been .045.

Well, a spark plug change will not alter fuel mixtures, period.

A spark plug change will not alter carburetor settings, nor will it alter closed loop fuel injection mapping.

It CAN alter how that fuel is burned.

Now, in an open-loop EFI system, like on most cars (but rare on boats), changing ignition components COULD have some VERY SMALL changes in mixtures, due to inputs from the O2 sensors about burn efficiency conditions, BUT, it would revert again to self-controll to deliver prescribed mixtures, thus no real, net, change.

The spark plug change caused a condition that is NOT "richer running".

IF it is "fouling" plugs, it is NOT from "richer mixtures", but from some other reason, as, again, a change to spark plugs will not alter fuel delivery curves.

If your engine is running excessively rich, it was running excessively rich before, and something about the previous spark plug setup was managing to not foul out under the conditions.

I have it resolved the problems. One plug wire was loose on the distrubtor cap, number one plug wire was off. Reattached plug wires and ran engine miss and backfire gone. Fuel issue still existed boat did not want to idel or run at low speed. Took boat for a test run last Saturday made it to the Green day mark west side of Knapps Narrows shoved throttle forward engine died. Towed back to marina by Boat Us. Checked filters for clogs in filter or lines no problems with filters no gas in filter at carb, carb dry no gas fuel pump died. Fuel pump was orginal 30 years old. No sin on this one.

Okay the new fuel pump is in and it no longer wants to stall, starts easy which is a big improvement and appears to idol smooth and sounds good. Spark plug wires are all on and connected to the correct plug and not crossed. Checked and rechecked. The engine is still laging and not responsive, has a miss at high speed and has lost 400 RPM. I did as sugested and removed the distrubtor cap and it is a charcoal gray inside you can not see any of the brass contacts. My question, is there a part number on the distrubtor cap somewhere and where it could be located. I can take the rotor with me and match it up. I looked the cap over real well and could not find a part number. Any hints on how to tell what make of distrubtor was installed. I looked on the bill for installing the electronic distrubtor and it does not have a part number or make of distrubtor. The other thing is that I am not sure an auto parts store will have a marine distrutor cap. It may have to it from a marine supply company. The wire set is not a problem I have the numbers for it.