*THE HULL TRUTH is the world's largest FREE network for the discussion of Boating & Fishing. Whether you're researching a new boat, or are a seasoned Captain, you'll find The Hull Truth Boating & Fishing Message Forum contains a wealth of information from Boaters and Sportfishermen around the world.
Welcome to the updated THT!
If you are having trouble signing in, please email feedback@thehulltruth.com with your username and we will help you. We thank you for your patience as we help you access the new site!
Random Quote: Give a man a fish and he will eat for a day. Teach him how to fish and he will sit in a boat and drink beer all day.
Last year and now I noticed the stardboard plugs (1,3, 5) all show a good bit of carbon deposit. Port side cylinder plugs look great. Wondering what causes build-up on just one side. Planning to take it to local servide dept but I like to research these kind of thing 1st to try to detect bs.
2002 motor with about 120 hrs on it. About 40 hours put on last year since plug change.
ukdave0 - 2/11/2007 3:04 PM Last year and now I noticed the stardboard plugs (1,3, 5) all show a good bit of carbon deposit. Port side cylinder plugs look great. Wondering what causes build-up on just one side. Planning to take it to local servide dept but I like to research these kind of thing 1st to try to detect bs. 2002 motor with about 120 hrs on it. About 40 hours put on last year since plug change. Thanks
2002 with 120 hours on it. Sure the fuel in the tank is not solid by now? [img]../images/emoticons/biggrin.gif[/img]
Is it running OK otherwise? Smooth and no shaking or vibrating? Does it pull its rated WOT rpm(5800-6000)
Forstartersand ifit was here Iwould do a cyl leak down test and check the throttle body link and sync on all . This would include a balancing of them ( need a Vacuum readingtool).
Andy
__________________ Andy Munao Our new parts site: www.simyamaha.com Yamaha Outboard Sales, Parts and Service 1-800-213-3323 parts@shipyardisland.com Click the logo to see our THT Vendor Forum
Yep, she'll do 5,900 sometime 6,000 WOT. Smooth except for the shakes at 600 rpm which seems somewhat common to other posts I've read.
I bought her used. When local dealer did the warranty reassign inspection, they did find compression on one side was different from other side. Just about a 15% difference. Can't remember which side was low.
Last year and now I noticed the stardboard plugs (1,3, 5) all show a good bit of carbon deposit. Port side cylinder plugs look great. Wondering what causes build-up on just one side.
Thanks
Besides the vacuum gauge balancing setup mentioned by SIM, use an infrared temperature gun to check the stb. cylinder head temp at idle. If it is not close to 140°F, then you may have a fautly or a fouled thermostat on that bank, making it run too cool for complete combustion.
Yamaha recommends that you use Ring Free even in the 4-stroke engines to help reduce carbon buildup on the plugs, rings, and valves.
__________________ ----------------
*... personally possessing more tools than talent !
__________________________________________________ _
Besides the vacuum gauge balancing setup mentioned by SIM, use an infrared temperature gun to check the stb. cylinder head temp at idle. If it is not close to 140°F, then you may have a fautly or a fouled thermostat on that bank, making it run too cool for complete combustion
Excellent point made by Seahorse. [img]../images/emoticons/thumbsup.gif[/img] If you do not have a infared gun, this would be easy for you to check yourself. Either by very carefully touching the cylinder head area with the engine warmed up and with you hand and comparing the two sides. Feel if your strb bank is much cooler then the ports.
Orthe F225 uses a self sealing t-stat meaing you do not need a housing gasket to inspect it. Pull the housing bolts off and remove it.
Andy
__________________ Andy Munao Our new parts site: www.simyamaha.com Yamaha Outboard Sales, Parts and Service 1-800-213-3323 parts@shipyardisland.com Click the logo to see our THT Vendor Forum
Carbon build up on Yami F225 plugs 
