1998 Yamaha 200 6 cylinder overheating issues

[Bill kubiak]

Hi my son has the above motor and has been having issues and has been paying a mechanic a lot of money and still has issues. He gets the overheat alarm. So far they have said it was salt clogged because of improper flushing and changed the thermostats and the water pump impeller and said they back flushed the motor., Now he was told they have to pull the heads to properly clean the water passages, so he came to me. He is almost 2k into this, I need to know if it is a big deal to pull those heads, don't know if he has a manual or not, I asked, he did not respond. I have been working on smaller motors all my life, the biggest were a 70 Hp Johnson and a 40 Merc 4 cylinder and on down to sailboat motors.
The boat will be here tomorrow afternoon. he was flushing after use with a flush plug in the side of the cowling and not running it.
First thing I plan to do get it running with ear muffs and listen to it and then check the temps with my point and pull the trigger thermometer to get an idea where the heat is
Need advice, help please

 

[99yam40]

lots of people have had overheating motors.

is it at low RPMs or high?

Flushing without running means stats are not open and will not get water circulated everywhere.
Look up Rydlyme marine scale remover some have had good results others maybe not.

If you have worked on blow boat motors and older motors then you know what it is like to break bolts and what to do for that
good luck if taking apart

 

[Bill kubiak]

I have just about every screw and bolt remover tool there is but it seems that with outboard there is alway one or two in the worst possible place that snap off and have to be drilled and tapped out. I am always hoping this one will not be that way. I have heard such good things about Yamaha and many of these overheating problems are user caused.

 

[99yam40]

you never said if over heat is at low or high RPMs.

Google Rydlyme and read up, it might save you from opening up the motor

 

[Bill kubiak]

Not sure if it is hi or low alarm overheat, the boat is en-route to me at this time. The Mechanic in the keys, who is suspect said the only thing left to clean all the salt out of that engine is to pull the heads, the new thermostats get clogged up with salt after an hour of running and it has a new impeller kit installed a week ago. He told my son it is around a 10 hour job and the required gaskets run well over 100 bucks and that is providing none of the head bolts break off

 

[99yam40]

I would think that if the stats plug with salt when running, you could drop the lower unit, pull the stats, hook up a hose to tube from pump , turn on water and run motor to warm things up and flush everything out.
A chemical to help dissolve the deposits would help.
Could be more than just salt

 

[Bill kubiak]

Got the boat, hooked up the water, fired it up, WOW loud!! Top of left cylinder bank gets so hot you cannot touch it, right side not nearly as hot, something is defiantly plugged and I think it might be that pressure control valve hidden away and hard to reach. We pulled both thermostat housings and checked the stats, the mechanic that installed them did a so so job of cleaning the water passageway behind the stats but not nearly to my level of what clean should look like. Any thoughts on how to get at that poppet valve or pressure control valve?

I do need some clarification, I have a seloc manual, and am still unsure what motor this is, some places they call it a 3.1, others a 3.3 and others a 3130 or 3342
The tab on the motor says it is an S200 TXRW, it has 3 carbs and is a two stroke, what have I got???

 

[mjf55]

S = saltwater series
200 = horsepower
T = Trim and tilt
X = 25"
R = Remote control
W = 1998

 

[Bill kubiak]

OK Great thank you for the info but in the manual it is referred to as the numbers 3.1, 3.3 etc which one is it??????

 

[mjf55]

Sorry Bill, but I cannot find that information. I do HIGHLY recommend getting the Yamaha factory service manual for this motor, not a Seloc. That will guide you correctly based on your model number.

Edit: Factory service info:
1998 200TLRW Service manual number LIT-18616-01-87

 

[Bill kubiak]

OK I got that info when we went to a dealer to get the gaskets,
2.6 V-6 200HP
3.1 V-6 225HP
3.3 V-6 250HP.

here is some info in case anyone else has a similar problem, Engine overheating and motor auto shifts to crawl model
Pull stats, yucky as hell, changed them, nothing changed,
New pump impeller, nothing changed except pisser got stronger
OK So we pulled the stats and left the housing off and added water thru the motor flush, no water came out the stat holes
Added more water thru the earmuffs, still nothing out the stat holes
Started motor, a few seconds later water comes out the state holes, good flow RH side not good flow LH side
Decided to add some ON/OFF acid in the left stat hole 3-4 OZ, saw it dripping out the prop hub, waited about two minutes and started engine, a gush of crap and yellow water out the left stat hole and had a better flow, did the same thing to the other side
put it back together and ran it for maybe 10 minutes with the two water supplies, no alarm
Then my son insisted we pull the heads anyway

Whole other story and it was a good thing we did, there was so much salt, crap and junk and completely clogged water passages, at this time we are still cleaning the heads. Yamaha dealer told us not necessary to pull the exhaust cover but it is necessary to pull and clean that poppet valve (water pressure control) as it is probably full of junk too and he warned us that valve has a lot of spring tension on it to be careful,

 

[mjf55]

Bill, good info and great progress. Couple questions
Any photos?
What is On/Off acid?
Did you pull the heads or the head covers or both?

The poppet valve does have a spring under the cover, but it is not that much force. However, if you are not expecting it, it can surprise you and cause you to drop a bolt.

 

[Bill kubiak]

My son took lots of photos and videos and is probably gonna post them on Facebook or you tube or something

On/Off is sold at West Marine, it originally was for bottom cleaning, but we found it gave outstanding and instant results on Stainless Steel fittings and removing rust stains on fiberglass, it is an acid based on muriatic acid, and will burn bare skin some. When used on fiberglass or SS you must use a natural bristle brush, any synthetic bristle brush will melt, and always rinse it immediately off.

My wife found that using it on the inside of the toilet bowl will immediately clean any remaining stains off after she scrubs it down with those Clorox toilet wands and immediately make it snow white again

We found that by pouring a small amount inside the stat covers after we brushed and cleaned them as best we could got rid of almost all the residual stuff left over in just one minute. You must have a hose handy and immediately rinse off SS, fiberglass, or whatever, use glasses and rubber gloves, you don't want it in your eye

We did both the head and the head cover, we found just as much and sometimes more blockage under the head cover

 

[mjf55]

Thanks Bill. If your son posts the photos, please come back and post a link.
I would expect more blockage under the head covers.
Reason I am so interested is that I am currently running a vinegar solition thru the cooling passages as a 'preemptive cleaning ' since I have the lower unit off ( 89 175hp).

 

[99yam40]

if it was as bad as you say, i would think the exhaust plate passages are bad also

 

[Bill kubiak]

Got it together and found that Poppet valve was more or less out in the open just below the electronics box. So we decided to open it up, lots of spring pressure and sure enough it was cruddy enough to warrant cleaning, we discovered a groove in the bottom of the boss on the motor and we all felt that some PO may have done that. When we put it back we decided to make it a two person job with each of us putting a short 10MM socket on an extension and lifting and pushing together against the spring pressure it went right back in. We started the motor and it ran really nice and cool, but there was a small dribble from the bottom of the poppet valve where that groove was. Tomorrow we are gonna pull it off again and fix the groove with JB weld, put it back together and if no leak then take it out for a test run for an hour or two

 

[Bill kubiak]

I'm back again, we pulled the poppet valve cover again and this time I cut the two tie wraps holding the hose to it and we pulled the valve cover off, and we found the leak, there was a big chunk of the part of the valve that goes into the hose corroded away, ran to the dealer and lucky us they had one in stock, went back, installed the new cover and no more leak. Took the boat down to the ramp for a quick test drive and all the issue he had were gone, it ran nice and quiet and smooth and did not overheat and we pushed it real hard to be sure and then we came back. JOB DONE and DONE WELL.

 

[99yam40]

good to hear it is good to go
how is he planning on keeping this from happening again?

 

[Bill kubiak]

He plans to flush using earmuffs as well as the built in flush and every two or three times out he plans to flush it with salt away. He bought the kit for that.

 

[99yam40]

let us know how it works out for him
most do not report back

I gues you all never opened the exhaust cover