Compression Test Results

[rad1026]

1989 Chaparral 2100SX, Merc 260. This will be my third season with this boat. My first boat. I thought I would do a compression test just to see how things are going. The engine hour meter shows 340 hours, I have no idea how accurate that is. Here are my results on a cold engine. I just didn't want to work on a hot engine so I didn't warm it up before I did the test.

1- 140, 2-120, 3-135, 4-120, 5-130, 6-119, 7-125, 8-120

So the starboard bank was really consistent right at 120 and the port bank gradually dropped to about 125. I was using a VERY old sears compression gauge, it seemed to hold the pressure fine. Any comments on my numbers are appreciated. And any thoughts on differences if I had warmed the engine up prior to the test. Thanks guys!

 

[Don S]

Re: Compression Test Results

Nothing wrong with those numbers, but, warm the engine at least for a minute or two to get the oil circulating. Then redo your test for a more accurate test.

 

[Lakester]

Re: Compression Test Results

1- 140, 2-120, 3-135, 4-120, 5-130, 6-119, 7-125, 8-120

hello,

those are good serviceable numbers! variation(s) could be lil more than carbon build up on piston, for example. all compression tests do is to give u a relative understanding as to the condition, usually... of the piston, bore, and ring combo of parts and to general condtion.

u can try it warm, or even with some oil in hole, but no doubt ur engine runs fine!

if u did a compression test 5 dif times, u would see 5 dif sets of numbers. all smiliar to each per test, but they vary.

it is always best to let a cold engine warm up to a heat soaked mode. this corrects all running clearances which are loose in a cold engine. cylinder bore scuffing is oft the result when a cold engine is gunned as piston to bore clearance is still on loose side.

like in aviation, for long service life, u always want... " oil in the green! "

regards,
lakester

 

[sarantis]

Re: Compression Test Results

Don't worry, the same had happpened to me.I bet if you warm the engine and try again the 120 side will become 140-150.

 

[Bondo]

Re: Compression Test Results

Ayuh,........ I Don't see a Problem either........

 

[180shabah]

Re: Compression Test Results

Go fishin', do your retest in the fall.