Compression Test Results

[tpondal]

K, did the compression check today. Brrrrr! It's in the mid 20's and windy. Here's the steps I took. I ran the engine with ear muffs until normal operating temp. Then hit kill switch, opened the throttle all the way, removed all spark plugs, and inserted comp guage into first cylinder. I cranked it over so that cylinder was compressed about 4 times, recorded reading, reset, and tested the same cylinder a second time. I repeated for all six. The average of the two readings are:

119.5 116.5
118.0 119.0
114.0 114.5

These results are positioned the same as if you were looking at the motor from behind. How do these look http://www.checkmate-boats.com/infopop/emoticons/icon_confused.gif

Now I'm not sure of the year. I was thinking this was a 1989 Merc 135 OB. I'm not sure why I thought that, though. Here's the serial number. (08242799) Can any one help identify it by this number?

Thanks again for your help

[tpondal]

K, did the compression check today. Brrrrr! It's in the mid 20's and windy. Here's the steps I took. I ran the engine with ear muffs until normal operating temp. Then hit kill switch, opened the throttle all the way, removed all spark plugs, and inserted comp guage into first cylinder. I cranked it over so that cylinder was compressed about 4 times, recorded reading, reset, and tested the same cylinder a second time. I repeated for all six. The average of the two readings are:

119.5 116.5
118.0 119.0
114.0 114.5

These results are positioned the same as if you were looking at the motor from behind. How do these look http://www.checkmate-boats.com/infopop/emoticons/icon_confused.gif

Now I'm not sure of the year. I was thinking this was a 1989 Merc 135 OB. I'm not sure why I thought that, though. Here's the serial number. (08242799) Can any one help identify it by this number?

Thanks again for your help

[JW]

HHMMMMMM, better double check your number. It didn't come up on the Mercury Parts express web site. I substituted a 'G' for the '8' and it came back with: MERCURY (SEA PRO)
Serial Number: 0G242799 Model Number: 1075217RD

Double check the serial, and we can try again. As for the compression, you want the cylinders to be within 10% max difference. Your numbers look good for an older motor. No frowing faces on there! Just run good Mercury 2 stroke oil in it and you'll be good. You might also want to check your guage, to make sure it's accurate. If you're guage is accurate, and you MUST have factory fresh numbers, then do a ring job and hone the cylinders.

Checkmates owned: 1995 Pulsare 2100BR/1995 Mercury Promax 225 2.5 EFI. 1995 Persuader 183/4.3 LX V6. 1992 Pulse 171/1992 Mercury XR6 150 hp 2.5 liter.

[tpondal]

Thanks. My eyes ain't what they used to be JW. I'll bet the 8 should be a B. I wasn't quite sure when writing it down.

I found the site you mentioned. When looking for a part it comes up with:
MERCURY (2.0L)
Serial Number: 0B242799 Model Number: 1135412BD

I just poked around on iBoats.com and found the following link:
http://www.marinshopen.se (Sweden, I think)
This has a chart for determining year based on serial number. It looks like this might be a 1988?

So, it sounds like these are expected readings for the year.

What would be my next step be for troubleshooting poor performance, bascially a poor hole shot? It does have a problem I've been bothered by. The engine rhythm can take a bit to smooth out when it's first started for the day. This also seems to have some affect on the spark plugs. If I get it warmed up good, smoothed out, and then put in fresh plugs, it pulls pretty good out of the hole. However, once it sits overnight and is restarted, this happens again. During initial take off the revs are just a little rough and it's flat power wise. Once the boat planes out it seems to clean out and go better. This is corrected, for a short time only, by changing the plugs.

[175checkmate]

Sounds like you may cave a carb problem. If the seats are not seating correctly you will get a rich condition as the fuel is overflowing the bowles. I had this on my 2.4, it tended to load up at idle and take off and then would clean it self out at higher rev's.

http://www.checkmate-boats.com/images/avatars/GusAvatar2.jpg


1975 Checkmate Tri-mate 2, 2.4 200+ / Sky jacker 6" plate / 25p Laser 2 prop

[MrWick]

I looked on marineparts.com and it looks like your motor is a 1989.A 135hp with a serial of 0B241xxx or higher is an 89 if I read the chart correctly.

[Chris]

What do the plugs look like after you've run them for a while?

I would say it's either a carb problem or ignition.

All my Mercs have done what you described when the stator is on the way out.

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Checkmate-Boats.com-The Fanatics Home!

[tpondal]

I looked this up on the site you mention MrWick. It looks like the 89's have a serial number that start with the letter "C". Am I reading this wrong? I would like to know the year. Thanks for checking.

Spark plugs that have been in the motor for a while (weeks), don't look too bad, I think. I'm not a mechanic, though. The center electrodes will be black, not a real thick black, though. Otherwise, they'll look pretty clean. (NGK) I tried Champions once. They seemed to foul out soon after installing them. I never tried them again.

[MrWick]

I was incorrect when I said the chart said it was an 89,an 88 fall between b241881 and c106xxx so that would make yours a 88.That was my mistake,when you get old stuff gets mixed up in your brain.Sorry.....