Strong Radio Interference from Yamaha 2-stroke

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Author Topic:   Strong Radio Interference from Yamaha 2-stroke

hanksaper posted 03-30-2004 08:47 PM ET (US)
Repowered montauk with 90 2-stroke yamaha.Now i'm getting interference which sounds like engine noise. Tried different radio,direct wiring to battery and different antenna - no difference.Moving antenna forward helps. The antenna is presently monted on starboard inner gunnel across from console and antenna wire runs inside rub rail to breaker box mounted on aft starboard gunnel then it is coupled to wire which runs through tunnel to console where it plugs into radio. Same set up before,but that was with 1988 90 JOHNSON-no problem until new engine. Tried resistor spark plugs -same problem. Noise not presenent if unplug antenna. Noise not always present-engine usually has to warm up before interference presene. Can squelch out but loose sensitivity.Suggestions?
Unrelated question-has anyone had a n icom 402 vhf that has significant reduction in voice volume when tranmitting?

Thank you.
jimh posted 03-30-2004 09:14 PM ET (US)
My Yamaha engine of similar design also has ferocious ignition noise. I think it must be endemic to those engines. It makes the VHF Marine Service radio useless when the engine is running.
I am sorry to hear that resistor plugs did not make a difference. I just bought $30 of resistor plugs planning to change them after I re-started the engine this spring. I'll let you know how they work for me in a few weeks.
dfmcintyre posted 03-31-2004 05:26 AM ET (US)
Hank -
One experiment you might try is to pick up a can of 3M spray glue, the kind artists or photographers use and a roll of aluminum. Lightly spray the sheets and attach them to the inside of the cover, then go for a run.
If that solves it, let me know. I have back issues of a magazine that may have a source for a foil lined foam material that might work.
Don
skred posted 03-31-2004 08:20 AM ET (US)
Just another idea: - I once installed a heat-sealing (for vinyl sheeting) machine. It used a radio broadcast tube to generate the the heat/current for the dies. The thing interfered with radios and TV's for blocks around the building. The solution was to build a wooden frame "cage" around the machine and staple metal window screen to the frame. No more RFI. You might try using metal window screening inside your engine cowling. It would not defeat the sound-absorption characteristics of the cowl liner like aluminum foil might.
BW23 posted 03-31-2004 04:52 PM ET (US)
I just did a quick search on Radio Shack, they offer a Part Number, 270-055 which should solve your problem.
It connects in-line of your 12 volt power source. There are other mfg's but wanted to provide you a despription of what to search for.
SS17 posted 03-31-2004 05:03 PM ET (US)
Jimh,
Don't know how many spark plugs you got for $30 but you may want to check out an online source. I just placed an order for some NGK plugs today for my Honda. The are $1.61 each plus 4.03 for ups. Works out to $2.00 per plug including shipping (for a package of 10.) I've also ordered plugs for 2 other motors and the prices are all about 1.61 each for NGKs.
I use www.rockauto.com. Cheapest I've found and good service.
Local dealers want over $5.00 each.
jimh posted 03-31-2004 06:30 PM ET (US)
I have little faith in a powerline filter from Radio Shack to suppress ignition noise sparking being propagated at radio frequencies.
You could simply test whether this would have any efficacy by just connecting the radio to an isolated battery. Since you are experiencing the interference on receive, a simple dry cell will run the radio for a few moments to make the test. Reception only requires a few hundred milliamperes of current from the battery.
I am sure you will find that the interference persists even when the radio power source is completely isolated from the boat battery. This is because the noise is not being induced from the power line; it is being transmitted via the "air" to the radio antenna.
I am curious to know the model year this Yamaha engine. My 1987 Yamaha is, as I mentioned, an enormous generator of radio frequency noise. It would be interesting to know if the Yamaha engineers have made any progress with this problem in the last 16 years.
islander posted 04-06-2004 06:49 PM ET (US)

I am just about to install an ICOM 402. Yikes ! I take it that the VHF is useless when running? (Have an 87 Yami 90.
JimH - What do you do, come to a stop and shut down to use the VHF?
If my antenna (4 ft wip) is mounted on my console, will this help?

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Author	Topic: Strong Radio Interference from Yamaha 2-stroke
hanksaper	posted 03-30-2004 08:47 PM ET (US) Repowered montauk with 90 2-stroke yamaha.Now i'm getting interference which sounds like engine noise. Tried different radio,direct wiring to battery and different antenna - no difference.Moving antenna forward helps. The antenna is presently monted on starboard inner gunnel across from console and antenna wire runs inside rub rail to breaker box mounted on aft starboard gunnel then it is coupled to wire which runs through tunnel to console where it plugs into radio. Same set up before,but that was with 1988 90 JOHNSON-no problem until new engine. Tried resistor spark plugs -same problem. Noise not presenent if unplug antenna. Noise not always present-engine usually has to warm up before interference presene. Can squelch out but loose sensitivity.Suggestions? Unrelated question-has anyone had a n icom 402 vhf that has significant reduction in voice volume when tranmitting? Thank you.
jimh	posted 03-30-2004 09:14 PM ET (US) My Yamaha engine of similar design also has ferocious ignition noise. I think it must be endemic to those engines. It makes the VHF Marine Service radio useless when the engine is running. I am sorry to hear that resistor plugs did not make a difference. I just bought $30 of resistor plugs planning to change them after I re-started the engine this spring. I'll let you know how they work for me in a few weeks.
dfmcintyre	posted 03-31-2004 05:26 AM ET (US) Hank - One experiment you might try is to pick up a can of 3M spray glue, the kind artists or photographers use and a roll of aluminum. Lightly spray the sheets and attach them to the inside of the cover, then go for a run. If that solves it, let me know. I have back issues of a magazine that may have a source for a foil lined foam material that might work. Don
skred	posted 03-31-2004 08:20 AM ET (US) Just another idea: - I once installed a heat-sealing (for vinyl sheeting) machine. It used a radio broadcast tube to generate the the heat/current for the dies. The thing interfered with radios and TV's for blocks around the building. The solution was to build a wooden frame "cage" around the machine and staple metal window screen to the frame. No more RFI. You might try using metal window screening inside your engine cowling. It would not defeat the sound-absorption characteristics of the cowl liner like aluminum foil might.
BW23	posted 03-31-2004 04:52 PM ET (US) I just did a quick search on Radio Shack, they offer a Part Number, 270-055 which should solve your problem. It connects in-line of your 12 volt power source. There are other mfg's but wanted to provide you a despription of what to search for.
SS17	posted 03-31-2004 05:03 PM ET (US) Jimh, Don't know how many spark plugs you got for $30 but you may want to check out an online source. I just placed an order for some NGK plugs today for my Honda. The are $1.61 each plus 4.03 for ups. Works out to $2.00 per plug including shipping (for a package of 10.) I've also ordered plugs for 2 other motors and the prices are all about 1.61 each for NGKs. I use www.rockauto.com. Cheapest I've found and good service. Local dealers want over $5.00 each.
jimh	posted 03-31-2004 06:30 PM ET (US) I have little faith in a powerline filter from Radio Shack to suppress ignition noise sparking being propagated at radio frequencies. You could simply test whether this would have any efficacy by just connecting the radio to an isolated battery. Since you are experiencing the interference on receive, a simple dry cell will run the radio for a few moments to make the test. Reception only requires a few hundred milliamperes of current from the battery. I am sure you will find that the interference persists even when the radio power source is completely isolated from the boat battery. This is because the noise is not being induced from the power line; it is being transmitted via the "air" to the radio antenna. I am curious to know the model year this Yamaha engine. My 1987 Yamaha is, as I mentioned, an enormous generator of radio frequency noise. It would be interesting to know if the Yamaha engineers have made any progress with this problem in the last 16 years.
islander	posted 04-06-2004 06:49 PM ET (US) I am just about to install an ICOM 402. Yikes ! I take it that the VHF is useless when running? (Have an 87 Yami 90. JimH - What do you do, come to a stop and shut down to use the VHF? If my antenna (4 ft wip) is mounted on my console, will this help?