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- - 200 Mariner (http://www.classicseacraft.com/community/showthread.php?t=20479)

Quote:

Well, ran it yesterday and it is still spitting intermittantly...but not overheating. But when I ran it up it was rough early then would get over 4800 rpm. Changed fuel filter and water seperator and still topped at 48-4900 rpm not 5600 as it usually does. I talked to the mechanic and he seemed to think it might have a blown head gasket or O ring. He thinks its blowing air exhaust into the water jackets which is causing the pulse. There was also alot of water coming out of the upper exhaust below the upper tell tale. It looks like something I could handle myself so I will give it a shot on tuesday or at least open it up and see. I remember the last day I had it out last year...I was wailing on it with a three man tube and it wasn't running all that good then. He happened to have a similer motor apart and the heads look somewhat accessable.
Does any of this sound like it might make sense?
I have literally gone through the entire cooling system at this point and it all looks normal. Starting to really lose patience.
Joe

Joe - Focus on what's changed since the motor last hit 5600 rpm. How much water is coming out the oval exhaust ports? If it's just spitting a little water out . . . that is totally normal behavior. O-ring heads came out on the 2.5L in 2001/2002 after mercury stopped producing Mariner. if you are worried about blown headgasket or water coming in . . . check the plugs and see if any look steam cleaned (like brand new). That's one of the signs of a blown headgasket . . . also check for low compression (on one or more cylinders same side).

Personally I think problem without knowing anything about the motor could be a lose plug wire, bad coil, etc. causing one cylinder not to fire (or fire intermittently). Get a spark tester and figure out if one cylinder isn't firing.

http://www.slickbiker.com/Slickbiker...lug-tester.jpg

No offense but that mechanic seems to be overlooking some obvious details and jumping into some pricey "unrelated" repairs. For a good referral you can ask on www.screamandfly.com for someone in the area that knows your motor.

Big difference between a mechanic and a parts changer - parts changers get very expensive since its your money.

Again, Thank you. I will get a compression gauge and spark tester. I noticed what looks like some silicone between one of the boots and plug wires...looks like a fix. The comp test should tell me if the gasket is blown too. I looked quickly at the site you linked and will start a thread on my problems later. The mechanic i saw is just a local and not sure he's really intune with OBs, my friend has had a lot of probs with him and started to take his Yamaha's to Weymouth. He's convienient and reasonable. I'm a self employed carpenter and times are a little tough to be fixing what he thinks the problem is. But I am really getting to know my way around this engine...at least that's one positive thing!
Will keep you guys posted...thanks again,
Joe

Jobu - Even though it's frustrating . . . My advice is to get a manual (I have an extra one) and beat your head against the wall to figure out your problem. Those motors are great!! They are strong, light, easy to work on, and relatively fuel efficient for a two stroke. Also If you need any parts for that motor, I have a garage full of them.

If you want to come swing by my place I can loan you a factory service manual for your motor.

I imagine Monihans Marine is the place that you are refering too. One of the mechanics there when I had a Yamaha 200 was awesome and extremely helpful and generous with his time!!

I'm going down tomorrow to try a compression test. I couldn't find a spark tester but will look on the way down. If I cant get the revs up I will pull it and take it to Bill's in Hingham, he's at least certified and deals 'em.
I appreciate it on the manual and I will try to track one down. Factory manuals are hard to find but seem invaluable...have a Seloc and it sucks.
I'll let you know and thanks.
Joe

Finally got a chance to get out to "Victoria's Seacrate" on Sunday and I changed the plug wires. While doing so I checked the plugs and sure enough the top port plug looked brand new. I also noticed the engine had a stronger fuel smell around it. The funny thing is that the tell tale seems to now be spitting almost perfectly. I am heading to Bill's Outboard this morning to get a gasket set but first I will check the spark and compression. I couldn't find a decent tester at either Sears or Pepboys (I like the one BigShrimpin showed in his post).Also the top starboard plug didn't look to dirty either but did seem to have a reddish color to it. When I ran it out of the water , it seemed to have alot of water coming out of the prop hub...is that normal? If it is the head gaskets I think it's something I can handle myself. But I'm hoping it could be a bad coil or even a plug.
Will post later if I can get anything done on her today.
Joe

Here are my results.
cold comp test
top to bottom port 94, 101, 103 psi
top to bottom strbrd 93, 102, 104 psi
head gasket?
out of ideas.
all six cylndrs have spark...top port plug is cleaner than rest but shows some sign of ignition.
???
Joe

Re: 200 Mariner head

The gasket looked frayed around the cylinder opening (new gasket has a metal ring but old one was tattered/ jagged around all openings also I see no metal left). There was a little bit or corrosion/salt between the water jacket opening and the top cylinder.
Also signs of salt inside the head walls...normal?
The top piston has some minor scratches dings in it as does the head in chamber. I'm thinking when the ring disintergated it got chewed up in the combustion chamber...?
As far as I can tell the cylinder walls look scratch free. Pistons have alot of carbon soot but other than the dings they look to be in tact...not new but decent.

Going to put it back together and have a look at the starboard side.

thanks for the info...I listen to it all.
Joe

Re: 200 Mariner head

Ouch!! The motor sounds like it may have been apart before . . . . Those compression numbers are NOT good for that motor. Healthy 2.4L and 2.5L 200 mercs/mariners will have roughly 125psi in each hole. Below 100psi is tear down time. Those head gaskets sound terrible . . . I have never seen gaskets blown as badly as you describe. Water (especially saltwater) entering the combustion chamber on any engine is VERY VERY bad . . . If the cylinder walls aren't scored . . . try replacing the head gasket and do another compression test (maybe even another gage). Make sure you use a good torque wrench and follow the instructions in the manual for torquing the head bolts . . . There is a pattern and procedure that should be followed. If you are back close to 120 - 125psi with the new head gaskets . . . then run it and get fuel through the motor.

Are any of the cylinder walls steel? or are they all still original chrome?

If you have any pics post them . . . locater pins can work themselves out and cause damage you describe, but they will score the cylinder walls.

Re: 200 Mariner head

Sorry for the late response...And thanks for your help. I feel like Luke Skywalker and you're Obi Wan Kanobi helping my mind mend.
Anyway the gaskets were pretty bad and the top strbrd piston looks like it has some damage. About an 1/8" is dissintergrated from about 1 1/2" of the circumference of the face edge. It looks like it may have siezed a while back and left a little piston on the cyliner wall. But the funny thing is that the cylinder walls look pretty clean, some very feint scores, almost less than the thickness of a hair.
The walls "(Are any of the cylinder walls steel? or are they all still original chrome?)" are definately not chrome and if I had to guess I would say there is less that 1/32" space all the way round the piston.
I haven't had time or energy after work to do anything but I will do a comp test this afternoon.
I followed the mfg specs on torqueing and seems to be ok 30 lbs. in X pattern.
This boat actually came from your neck of the woods. Was Called 'Summer C's' white hull red letters 23 scepter. I bought it from Nauset Marine.
At this stage time and money is running out so I'm gonna put her in and hope she'll at least plane off and get me a few miles to the bass/flounder and have the block pulled in the fall and take it home and try a rebuild.
What do you think? or cheaper to save up for a rebuilt power head....What kind of numbers would you say that would run...if you know?
Any way I'll keep checking for your reply and keep you up on it...right now going to fix my roof and get some bottom paint on the old girl.
Thanks again,
Joe
I will try to send you some pics too