Outboard - Mild steel bolts

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NorthRising

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On re-fitting my 4 year old outboard to boat I accidentally knocked off the plastic cap on the gear shift that provides access to its bolt and I noted a pile of brown flakes (rust), and a heavily rusted bolt. Somewhat surprised that kit for marine use would use mild steel.

Would it be normal for an outboard manufacturer to use a mild steel bolt to afix the gear lever to the engine?
 
Gee! That's what I call cutting production costs! But then how many manufacturers of inboard motors would use s/s bolts?
 
NorthRising said:
On re-fitting my 4 year old outboard to boat I accidentally knocked off the plastic cap on the gear shift that provides access to its bolt and I noted a pile of brown flakes (rust), and a heavily rusted bolt. Somewhat surprised that kit for marine use would use mild steel.

Would it be normal for an outboard manufacturer to use a mild steel bolt to afix the gear lever to the engine?
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Sadly, the answer is YES. For example the Honda 2.3hp with a rrp of over £600 is all mild steel stuff, including the rocker cover, which being exposed to salt water air and splashes rusts away quietly unnoticed.

Rather like modern cars, the cynic in in me reckons that the manufacturers don't want it to last more than 6-8 years, but which time any significant repair becomes uneconomic. Once mild steel bolts rust beyond a certain point, the whole thing will be very difficult to take apart...
 
dartmoor said:
Sadly, the answer is YES. For example the Honda 2.3hp with a rrp of over £600 is all mild steel stuff, including the rocker cover, which being exposed to salt water air and splashes rusts away quietly unnoticed.

Rather like modern cars, the cynic in in me reckons that the manufacturers don't want it to last more than 6-8 years, but which time any significant repair becomes uneconomic. Once mild steel bolts rust beyond a certain point, the whole thing will be very difficult to take apart...
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+1

Caught and burnt, Honda 4 stroke, 2hp (Oz model) rocker cover bolts or studs corroded and the plate and the cost of removal and replacement was more than a new outboard. We now have a cheap Chinese outboard, we have no great expectations, treat it like rubbish but it runs and runs and runs, but only 4 years so far.

Jonathan
 
charles_reed said:
I know of no marine motor manufacturer, OB or inboard who uses stainless bolts - though some do where the absence would be obvious.
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And you get some who put thin chrome plate on them. In my opinion that tends to look almost worse, since as soon as you have put a spanner or socket near them, the corners start peeling :(
 
NorthRising said:
On re-fitting my 4 year old outboard to boat I accidentally knocked off the plastic cap on the gear shift that provides access to its bolt and I noted a pile of brown flakes (rust), and a heavily rusted bolt. Somewhat surprised that kit for marine use would use mild steel.

Would it be normal for an outboard manufacturer to use a mild steel bolt to afix the gear lever to the engine?
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This one is a Yamaha F6C (6HP 4 stroke). Once I have my old engine (1986 Mercury 8HP) up and running I'll swap them over and have a look and see if I can replace the parts before it is too late.
 
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I helped my pal repair his 9.9 Yammie where the long studs holding the leg sections together had rusted and swelled and burst the leg sections. A hell of a job to cut out the legs section around the drive shaft, water pipe and gear linkage. I was very surprised that mild steel was used in this application however when I bought a new Tohatsu 20HP engine recently I was disappointed to see that despite my high regard for Tohatsu engines the studs/nuts holding the leg together appeared to be cadmium plated MS.
 
omega2 said:
stainless will harden and break
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I know of no mechanism for that other than significant plastic deformation. Stainless fastenings are in use by the million in all sorts of engineering applications without significant problems. LNG compressors consuming 50 - 90 megawatts are entirely built from 300 series stainless steel and their bolts neither harden nor break.
 
Outboard motors use a special steel alloy that contains a lot of lead, this is so the heads snap off easily when you want to take them apart. This is so you give up & then buy a new one.
 
I had a close look at my newly acquired Honda 2.3 yesterday and that's got rusting ms holding the cover on. Goodness knows what delights are inside. I'll replace what i can with ss. Never had this issue with my Seagull, it is always covered with a film of oil! Expect it Will outlast the Honda though.
 
My old Johnson of about 1986 vintage has most of the bolts made of staineless steel. Yes it does corrode into the alloy casting but frequent dismantling and lots of grease seems to stop any problem. However strrangely there are bolts and rods in the tilt mechanism which are of rusting steel. Strange because it is very clear to see from a distance.
olewill
 
coopec said:
Kieth

Is there really an iron/lead alloy?
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I suspect that lead and iron are mutually insoluble, so they could never form an alloy. However, many modern metals described as 'free machining' contain 1-2% of lead, e.g. brass, steel, bronze, etc. Some others have inclusions of manganese sulphide. The addition does nothing for the material but allows machining at high speed, with the lead acting as a lubricant. The steel version is known as 'leaded steel' http://www.steelexpress.co.uk/engineeringsteel/EN1APb.html
 
Honda are notorious for soft mild steel fasteners. Fully agree that the rocker covers need to be salt resistant but regarding fastners if they are soft mild steel they can be removed if they break. If they are stainless forget it and throw it in the bin. I replace all of mine now with zinc plated mild steel.
ghostlymoron said:
I had a close look at my newly acquired Honda 2.3 yesterday and that's got rusting ms holding the cover on. Goodness knows what delights are inside. I'll replace what i can with ss. Never had this issue with my Seagull, it is always covered with a film of oil! Expect it Will outlast the Honda though.
Click to expand...
 
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