OEM Plug Recommendations

[Texasmark]

You know, you just have to keep asking questions.

Still working my clutch dog rattle problem. Figure if I can smooth out my idle, I can reduce it since I am running a big bore 3 cyl and idle (675 rpm) is rough for obvious reasons d .

So I'm yacking away on here and Silvertip kicks in with a suggestion on changing type of plugs (like he did with a similar engine); from surface gap to a more conventional style.....NGK is the brand. I never did like the idea of surface gap anyway, seems like you are putting a short circuit right across the electrodes.

So I go to the NGK site and stark digging around for information. First of all I go to their plug selector and brouse thru the plug types offered for a couple of Merc engines in particular. Noticed both use the surface gap.

Plug in that model number for info concerning it and lo and behold, find out that the surface gap is recommended for two extremes of operation to reduce fowling: One is continuous WOT operation and the other is long periods of trolling.

Hmmmmmm. I do neither, so I guess I don't have to stay with the OEM recommended plug. d

So, the plugs Silvertip recommended are purchased and installed. All I have to do now is wait till it warms up a tad and take her out and see if this helps. Even if it doesn't they will probably stay for the reason stated.

Moral of the story is don't blindly accept what OEM's put in front of you. They do what they do for a reason. You need to understand the reason and if it doesn't apply, then it looks like you are open to change things up a bit; iif you are of a mind to do so.

We all have our own little world of boating with our unique situation. OEM's have to build equipment for use for everyone of all talents, in all the world, under all conditions, and hope they have a winner. One heck of a design task.

My hat goes off to them, but like I said, if you're careful, and do your homework, no reason why you cain't tweak the recipe for your little nitch. d

Mark

 

[JB]

Re: OEM Plug Recommendations

While I don't really disagree with your premise, Mark, I wouldn't suggest care and homework to some who haven't a clue what either is.

A lot of scrap heaps are populated with the consequences insufficient care and incorrect homework.

 

[Texasmark]

Re: OEM Plug Recommendations

True-true. For every action there is a reaction and I think this one is a no brainer.....for me......er ah I think. :%

Mark

 

[Silvertip]

Re: OEM Plug Recommendations

Since I started this topic with Mark I suppose I should explain my rationale. First, I like JB, do not recommend that everyone run out and throw a set of conventional plugs in their engine if surface gaps are recommended. That said, I've been around the block a time or two and have owned lots of two stroke equipment and have experienced a problem with every engine for which the manufacturer recommended surface gap plugs. There is no arguement that they work well for sustained high-speed operation, but my experience is that they do not fair well at trolling or even moderate speeds since they carbon-track very easily -- and one spec is all it takes. Once that happens it is not likely that track can be burned off by "letting it hang out" for a mile or two. I owned a snowmobile that had a horrible low speed problem in that regard. Unfortunately I could not use a conventional plug in that motor so I bought a small brush with brass bristles and on a 50 mile trip I was almost assured I'd have to dig it out and clean the plugs off or if they were really tracked, I'd need to replace them. At any rate, I'm very happy with the performance of conventional plugs in this engine. It starts quickly, idles nice, and if they weren't currently gunked up with fogging oil I'd snap a picture and post it. They burn perfect and currently have 50 hours on them. I may just slide one surface gap plug in #2 and just run it until is begins to act up. I would bet money it will be #2 plug that's the culprit. Finally, upon return home from a lengthy trip I always pull the plugs for a read. Using a small, bright LED pen light I check the piston crowns for any evidence of detonation or deterioration. This process takes just a few minutes and can prevent a serious burn down -- provided of course the issue is diagnosed and fixed.

 

[Texasmark]

Re: OEM Plug Recommendations

Back to my comment about this one being a no-brainer for me.

Silvertip has done the necessary research, (seems to be) correct plug selection, and test evaluations for me. Since we have the same engines, except for hp differences, I feel very confident with this change and he has done all the preliminary work.

Had he not, I would have to start from scratch, spend a lot of time and do a lot of guessing, with my fingers crossed, that I was heading in the right direction and not tearing up anything in the process.

Course I could always leave well enough alone. Well it's not well enough. I want more, so change is in order.

I was going to test it this morning, but it was 20 outside and I think I'll just stay here in the house and yak on iboats next to the heater. d

Thanks Silver,

Oh and Silver, my comment the other day about what do you mean thanks (about iboats service on the bimini), was a curiousity statement. Do you do work for the site? No biggie, just curious. Helps to know what cap the guy is wearing who is providing you with info.

Mark

 

[Silvertip]

Re: OEM Plug Recommendations

Nope -- I don't work for iBoats. I'm just the type of guy that likes to give credit when due and I feel iBoats has gone over the top by providing these forums. By far the best I've run into or I would not be here. When I said "that's what WE like to hear" I was merely indicating that we (as in the members of this forum) like to hear. One more thing Mark -- if you think 20 degrees is cold, we had 12 below zero up here in the tundra this morning. With the wind today, bare skin will freeze in a matter of minutes. That ain't fun -- been there & done that.

 

[roscoe]

Re: OEM Plug Recommendations

Brrrr, we are still at -10F, with -33F wind chill.

Been in a lot worse, but it has chilled me thru to the bone today.

 

[kenmyfam]

Re: OEM Plug Recommendations

Back to my comment about this one being a no-brainer for me.

Silvertip has done the necessary research, (seems to be) correct plug selection, and test evaluations for me. Since we have the same engines, except for hp differences, I feel very confident with this change and he has done all the preliminary work.

Had he not, I would have to start from scratch, spend a lot of time and do a lot of guessing, with my fingers crossed, that I was heading in the right direction and not tearing up anything in the process.

Course I could always leave well enough alone. Well it's not well enough. I want more, so change is in order.

I was going to test it this morning, but it was 20 outside and I think I'll just stay here in the house and yak on iboats next to the heater. d

Thanks Silver,

Oh and Silver, my comment the other day about what do you mean thanks (about iboats service on the bimini), was a curiousity statement. Do you do work for the site? No biggie, just curious. Helps to know what cap the guy is wearing who is providing you with info.

Mark

Wow Mark, 20 is like tropical to us at the moment. We are all freezing our asses off right now in Ontario. In fact I think my outboards skeg may freeze off if i touch it !!! LMAO

 

[Texasmark]

Re: OEM Plug Recommendations

Thanks Silver for the clarification.

Guys, my hat goes off to you. Back when Purdhoe Bay oil field opened up in Alaska, Arco Oil Co. was down in Houston (TX.) recruiting folks to go up there and build it.

I had this wild idea that I'd like to do that..for the money and the adventure. The wife says if you do you will go by yourself. Geez the intuition of the female mind.

Still married and don't regret it. d

Mark

 

[Texasmark]

Re: OEM Plug Recommendations

Silvertip.

I got her out the other day with the new plugs and here's the lineup.

1. Starting, much quicker, although I fiddled around after the initial kickoff and it took a while to figure out the new sequence.

2. Restarting after initial start, even after extended stop for fishing was instantaneous with nothing but the key; much better than before where I needed to prime it.

3. I regained the 2 mph I lost for some reason. When I bought the boat It ran 52 speedo. Later on it dropped off to 50 and I thought it was the summer weather. Winter came and it was still 50.....got a GPS and the 50 was really 48. :% Well, now it is back to 52/50 GPS.

4. Rpms were a comfortable 5600 (5500 max rated). Now they shot up to 5900. I'm running a 24P XP Ballistic and I can't find a prop in that hub size with a higher pitch. :% I just don't know what to do :'(.........yeah right 8) ).

5. Once the engine warmed up rattle was significantly less but still had some.....and that's ok. I can make it go away at a lower rpm now and I can live with that.

So the plugs will stay and thanks for the heads up.

Looks like I am a happy camper.

Mark

 

[Silvertip]

Re: OEM Plug Recommendations

Cool! Glad the switch worked for you. Read the plugs frequently until you are comfortable with the switch. Although surface gap plugs are not "new technology", they are certainly not as "old tech" as conventional plugs. My point? Sometimes you just can't beat "old tech". d

A WARNING to anyone else running surface gap plugs! If you followed this thread and think you want to change to regular plugs -- think it through. You best have a reason for doing it. If your engine runs fine and are not having any starting/restart/idle/performance issues, stay with what's recommended. The change Mark and I made were for specific reasons. If you do have engine issues, make sure all other systems are at spec before even thinking about a plug type change.

 

[Texasmark]

Re: OEM Plug Recommendations

Hey Silver. You did a stellar job of defending yourself for the other wannabees, but what about my 300 rpm increase that I'm going to have to deal with. 8) 8) 8)

Love it.

Mark

 

[Silvertip]

Re: OEM Plug Recommendations

Seems to me you have four options in that regard:
1) Throttle back 300 RPM :'(
2) Buy a new prop 8)
3) Add a few sand bags, :} or
4) Put the surface gap plugs back in. :|

 

[Texasmark]

Re: OEM Plug Recommendations

Gotta LMAO on those options. I know that you knew they ALL were unacceptible or you wouldn't have amused me with them.

I really didn't expect the numbers to change like that; but there I was moving right along and reading the gauges. Everything was the same as the last trip I made with the old style plugs; load, lake, weather, time of year.

Mark

 

[Silvertip]

Re: OEM Plug Recommendations

Forgot a fifth option -- drop the engine down a hole or two! d