Yamaha 9.9

Post here for issues with outboard engines (i.e Yamaha 9.9) on PDQ yachts
Old PDQ Message Board
Site Admin
Posts: 522
Joined: Sun Apr 25, 2004 11:08 pm

Yamaha 9.9

Postby Old PDQ Message Board » Mon Apr 26, 2004 5:50 am

Yamaha 9.9

Posted by David West on October 12, 2002 at 13:55:00:

My Yamaha 9.9 engine which is five years old but regularly serviced with about
1000 hrs. use. It has for the second time burnt out the stater. There is of
course attendant damage to the fly-wheel and various wiring. The first time this
happened there was damaged to the CDI which had to be replaced twice. Perhaps
because I am continuing in a learning process on how to deal with these failures
it has been very expensive and extremely time consuming to get things put right

I am begining to get fed up with this

Now when ever I ask a mechanic about the problem the first question they ask me
is: What batteries are being charged? When I tell them that I am charging my
bank of three house batteries there is a brief pause for langhter followed by
the statement that the engine should never be used to charge a deep cycle
battery. A couple have told me that this is clearly stated in the Yamaha service
manual

I recently contacted PDQ and was given a cogent explaination that the output
load on the engine does not matter except that of course there is limied
amperage compared to inboard motors. I was told that this was not a problem that
has troubled other owners. Perusal of these pages might suggest that this is not
the case. I spoke to Colin Swithenbank who kindly spent much time explaining
that it was perfectly OK to continue using the motor output for the house bank

The mechanics tell me to rewire the boat and buy a generator for the batteries
(I already have two solar panels and a wind generator)

I don't know what to believe but I do want to avoid further problems. This time
the damage is so extensive that a new motor is recommended

Any ideas anybody?
David West

Follow Ups:

Re: Yamaha 9.9 Dan Hofmann 04:28:42 10/15/02 (0)
Re: Yamaha 9.9 Chet White 18:39:42 10/13/02 (0)
Re: Yamaha 9.9 Chet White 18:35:21 10/13/02 (0)

--------
Re: Yamaha 9.9

Posted by Dan Hofmann on October 15, 2002 at 04:28:00:
In Reply to: Yamaha 9.9 posted by David West on October 12, 2002 at 13:55:00:

I agree with Chet about the stator out put. I would suggest that you get a
tachometer and put it on so that you do know what RPM's you are running and
definitley run at 3/4 throttle, not much higher. Engine longevity suffers with
full throttle operations

Motoring on a sunny day, you will see your batteries go into the red zone very
easily.

Follow Ups:

Re: Yamaha 9.9

Posted by Chet White on October 13, 2002 at 18:39:00:
In Reply to: Yamaha 9.9 posted by David West on October 12, 2002 at 13:55:00:

Hi David,
Just got back from the POA meeting in Annapolis. Wish I could have met you there
to talk about this

#1 - The Yamaha four-stroke should give at least 2000 hr life even in salt water
if the oil is changed every 100hrs, the filter cleaned, and the cooling system
flushed occasionally

#2 - Those mechanics are wrong. The engines do not care how many batteries or
what size they are hooked to as long as they are 12V. Each engine will charge
about 8A at normal power until the batteries are charged. Here starts the
problem. Being a permanent magnet(in the flywheel) charging system, there is no
way to reduce the output when the batteries are fully charged. The voltage then
continues to rise from a normal 14.1V max on to 17V or higher. This boils the
acid in the battery and will likely ruin it

My solution is to plug in a 150watt lamp powered by my Freedom inverter. This
pulls about 15amp of DC power and the system is balanced. The problem is to
remember to turn the light off when shutting down the engines or you quickly run
down the batteries. There is a regulator available by Flexcharge (about $100)
that will shunt the output of the motors to a dummy load at some preset voltage
(14.1V) but I can't think of a good 150watt 12V dummy load

#3 Several of us have had to replace CDI units and others have had no trouble. I
personally think that the CDI overheats easily because of its location, damaging
its internal components, particularly if the engine is run at high power and
there is some salt buildup in the cooling passages. I also believe sometimes
there is preignition due to excess spark advance at full throttle causing excess
heat and subsequent failure of CDI. There may also be a stator problem involved
here. You might try backing off of full throttle a bit to improve life of the
engine

#4 Lastly, The starter has nothing to do with charging system. I would suspect a
low voltage at the starter which causes excess amp draw and heat destroying the
starter. Check for any resistance in the cabling to the starter from the battery
like a bulkhead connection and limit the spin time to about a minute with a 5
minute cooling period before the next try

Wow!! I think I overdid this,
Good Luck,
Chet White, Allezcat, 36010

Follow Ups:

Re: Yamaha 9.9

Posted by Chet White on October 13, 2002 at 18:35:00:
In Reply to: Yamaha 9.9 posted by David West on October 12, 2002 at 13:55:00:

Hi David,
Just got back from the POA meeting in Annapolis. Wish I could have met you there
to talk about this

#1 - The Yamaha four-stroke should give at least 2000 hr life even in salt water
if the oil is changed every 100hrs, the filter cleaned, and the cooling system
flushed occasionally

#2 - Those mechanics are wrong. The engines do not care how many batteries or
what size they are hooked to as long as they are 12V. Each engine will charge
about 8A at normal power until the batteries are charged. Here starts the
problem. Being a permanent magnet(in the flywheel) charging system, there is no
way to reduce the output when the batteries are fully charged. The voltage then
continues to rise from a normal 14.1V max on to 17V or higher. This boils the
acid in the battery and will likely ruin it

My solution is to plug in a 150watt lamp powered by my Freedom inverter. This
pulls about 15amp of DC power and the system is balanced. The problem is to
remember to turn the light off when shutting down the engines or you quickly run
down the batteries. There is a regulator available by Flexcharge (about $100)
that will shunt the output of the motors to a dummy load at some preset voltage
(14.1V) but I can't think of a good 150watt 12V dummy load

#3 Several of us have had to replace CDI units and others have had no trouble. I
personally think that the CDI overheats easily because of its location damaging
its internal components, particularly if the engine is run at high power and
there is some salt buildup in the cooling passages. I also believe sometimes
there is some preignition due to excess spark advance at full throttle causing
excess heat and subsequent failure of CDI. There may also be a stator problem
involved here. You might try backing off of full throttle a bit to improve life
of the engine

#4 Lastly, The starter has nothing to do with charging system. I would suspect a
low voltage at the starter which causes excess amp draw and heat destroying the
starter. Check for any resistance in the cabling to the starter from the battery
like a bulkhead connection and limit the spin time to about a minute with a 5
minute cooling period before the next try

Wow!! I think I overdid this,
Good Luck,
Chet White, Allezcat, 36010

Return to “Outboard Engines”

Who is online

Users browsing this forum: No registered users and 1 guest