Plugs Rusting on 1997 Force 120Hp

[TimeOut]

Motor is 1997 120Hp Force, Exhausts through hub.<br />I’ve had moisture in the engine causing the plugs to rust (#1&2). Took to the shop, advised them of the problem. They did a compression which tested all OK so they left it up to me advise them what to do!. (I thought they were the professionals!) Asked them to do a head gasket as I though this was the obvious thing to do and they said there seemed to be a bit of water tracking from the exhaust plate gasket. Had head gasket re placed, side plate gasket replaced. $400 later, seemed to fix the problem Have been for a run last week (Motor ran fine) and re checked plugs this week. I now have rust forming on #1,2 &4.<br />Have pull carbs off and removed Reed Valves blocks all OK. There is no rust forming on the Crank etc.<br />Boat is garaged. <br />Has anyone got any ideas what the problem may be? <br />Thanks<br />Alan, Christchurch, New Zealand

 

[The Marine Doctor]

Re: Plugs Rusting on 1997 Force 120Hp

Other than a cracked block...Have you been using an Ethynol gas?<br /><br />TMD

 

[TimeOut]

Re: Plugs Rusting on 1997 Force 120Hp

Hi TMD<br />No ethanol based fuel available in New Zealand. <br />I have owned it from new, and have used 91 octane unleaded with the occasional 96 octane unleaded in winter, also have used Mercury Quicksilver 2 stroke Oil all its life as well.<br />Engine has only done 230 hours.<br /><br />Regards<br />Alan

 

[The Marine Doctor]

Re: Plugs Rusting on 1997 Force 120Hp

Hmm.<br /><br />I would suspect that a gasket has blown through again.<br /><br />Has the engine ever been overheated?<br /><br />You say that there is no internal rust. ie...crank ect.<br /><br />The water must be comming from the exhaust side, or the base gasket.<br /><br />Are the plugs milky?<br /><br />TMD

 

[TimeOut]

Re: Plugs Rusting on 1997 Force 120Hp

Hi TMD<br />No, engine has not over heated.<br />The crank has no signs of rust.<br />I have ran the motor for 15min. in a tank at 1400rpm last week.<br />Removed plugs, non showed any signs of being milky. All had the usual 2 stroke residue.<br />Put plugs in finger tight, Checked daily and no signs of rust after 1 week.<br />last evening I run the motor on muffs which is my usual way flushing after being in the sea.<br />Ran at 1100rpm for 6min. Check plugs non were milky but # 2 showed a reddish residue which to me was rust based. Checked 24hours later, #1 & 2 plugs rusted up 3 & 4 OK<br />What do you think- Head Gasket, Cracked head, Megaphone gasket or ?<br />Re your 1st response re do I use Ethanol gas.<br />Well as of late last week the NZ Govt has approved that Fuel with up to 10% ethanol will be introduced from around 1st Dec 2003.<br />Is this going to lead to problems in the future? If so what.<br />It is not clear if we will have a choice or all fuel will be mixed with ethanol. <br />Regards<br />Alan, Christchurch, NZ

 

[force01]

Re: Plugs Rusting on 1997 Force 120Hp

allan,<br />your motor will do just fine on the new fuel. it is possible that your exhaust gaskets may have a slight leak causing your exhaust chamber to do what is called steaming which will put a water vapor mist back into the cylinders when the motor is shut off, i have been specializing in forces for 20+yrs occasionally i do run into rust on the spark plugs with no complaints from the customer. you have already had the gaskets changed, you might be making more out of this than it really is. good luck, bret forceparts@yahoo.com

 

[The Marine Doctor]

Re: Plugs Rusting on 1997 Force 120Hp

Anytime water of any kind is found within the cyl's it time to hunt it down and find out why.<br />Ethynol gas...attracts water. Its ok for use in vehicles as the vehicles use the gas up quicky and generally have more in the tank, so water is not an issue.<br /><br />Is your boat aluminum? Do you have an onboard tank?<br /><br />This combination tends to make water, more readily in the fuel tank than a Fibreglass boat.<br /><br />They are really prone to condensation.<br /><br />TMD

 

[TimeOut]

Re: Plugs Rusting on 1997 Force 120Hp

Hi TMD<br />Thanks for info- Just been for a run today-<br />3 hours running- Flushed on Muffs- 4 Hours later<br />1& 2 rusted real bad 3&4 on the way.<br />Going to book her into the shop tomorrow to have sorted out!<br />I will let you how I get on.<br />The Boat I have is a 97 Capri Bayliner.Always have kept the tank full to avoid condensation.<br />If we have a choice of fuel will stick to the non ethanol base fuel.<br />Regards<br />Alan

 

[IMPATIENT 1]

Re: Plugs Rusting on 1997 Force 120Hp

allan,<br />your motor will do just fine on the new fuel. it is possible that your exhaust gaskets may have a slight leak causing your exhaust chamber to do what is called steaming which will put a water vapor mist back into the cylinders when the motor is shut off, i have been specializing in forces for 20+yrs occasionally i do run into rust on the spark plugs with no complaints from the customer. you have already had the gaskets changed, you might be making more out of this than it really is. good luck, bret forceparts@yahoo.com

bret, could you take alook at my thread , give an opinion you may have seen my issue before if you're the man on force, its got me stumppppped