Hi what is the alternative spark plug to the NGK CMR7H ideally BOSCH?I have always used BOSCH plugs in my cars & motorcycles so its just preference,hopefully they make an alternative for my ZENOAH,thanks in advance

Cross reference charts I have looked up show no BOSCH or Nippon Denso replacements for the resistor equipped CM series NGK plugs.
Not to worry, the NGK's are great plugs IMO.

** DON'T make the mistake of using a NON resistor plug with a Radio Control model !!

Gotta go with Scott on this one!!! Used a non resistant unknowingly in my first gas airplane!!! Have ya ever seen the pile of sticks a 1/4 scale (85") Edge 540 can make when it hits the ground at about 95mph!!! UUUUUUUGGGGGGLLLLLLLYYYYYYYY!!!!!!!!!!!!!
I'm pretty sure the same result would be just a matter of time>>>

Hi Scott & Isuzu.

I am really no good in reading technichal terms in english.
"A NON resistor plug", does that mean that the plug must have some kind of insulation in order not to disturb the radiosignal to the boats receiver?

Cheers!

Woodie.

Hey Woodie... Go check this out. I'm sure this will explain it alot better than I can www.ngk.com/sparkplug411.asp?kw=Resistor&mfid=1

Thx Isuzu.

By reading your link I see that my guess was just about right.

But I tell you. It's becoming scaring how many basics one has to know about just to get a boat running. Nobody ever warned me about this!
Do you know about a site or a book with some simple step-by-step instructions for idiots (like me) about setting up engine and electronics? I really don't want to invent or discover it all by myself.
(Instructions about finer tuning is not what I look for).

Any help anytime is welcome.

Cheers!

Woodie.

Woodie,
At the point this GAS rc boat hobby is now it is sooooo important that one tries to get involved in a club or group of individuals that has "been there and done that" While what we do is not high tech, there are some very important DON'T DO's

Spend some time reviewing the depths of Reviews, How too's, Etc on this site, it should hit 75% or better the basics, any thing else you question .... ASK !

Hi Scott yes built a boat early this year,my first boat with a MCculloch weedy engine and wondered why when i started it it throttled up on its own,I had a Champion CJ8 plug in it which obviously does,nt have a resistor.I knew it was the engine as i had just checked my radio equipment and all was fine prior to starting the engine with no glitches at all.Anyway put the plug from my Zen in and all was fine.Things could have been loads worse if the boat had,nt have throttled up immediately like a run away boat.Thanks for looking about the other plugs anyway and keep up the good work on a truly excellent site.DAZZIDO

Friends,

I met this topic about BOSCH plug.

We have a very unpleasure experience with BOSCH, engine JG 26 on Zenoah end was damaged.
It was 1 (one only) run on full throttle.
A small part of central electrode was broken inside cylinder and broke a piston and liner.

Day of race was finished to very fast boat.

The BOSCH is a very good name, but I never use it in my boats.

Sorry about it.
Sergey