• This site contains eBay affiliate links for which Sea-Doo Forum may be compensated.

How Bad is a High Compression (180) Cylinder on a 4 TEC?

Status
Not open for further replies.

Tomenyt

New Member
I'm looking at buying a 2003 Sportster 4 TEC and it looks to be in good shape - but when I took it to a dealer for a pre-buy inspection, the compressions came back 160, 160, 180! The mechanics were concerned about the 180 - too high. What's the problem and risk here?
 
Do you know how many tests they performed? If I saw that, I would pull the plugs and discconect injectors and coils and turn the engine over to see if any fogging oil etc came out of the cylinder that's high. If you see the same numbers after 3 consecutive tests and that cylinder came back at 180 you have a problem. Was the engine recently rebuilt? If so, they may not have machined (decked) the cylinder head or possibly re-used the cylinder head gasket.

If I were you I would just pull the plugs spin the engine and try comp test again, if numbers are the same find another boat. My $0.02
 
I'm pretty sure they did one check. The boat has been sitting for awhile (since summer) and I don't know if it was winterized - but I was assuming that this shop would that that into consideration. The engine has not been rebuilt and we are taking it to another shop where it has been serviced before to check it again. I'll refer to your suggestions and appreciate the help.
 
I'm pretty sure they did one check. The boat has been sitting for awhile (since summer) and I don't know if it was winterized - but I was assuming that this shop would that that into consideration. The engine has not been rebuilt and we are taking it to another shop where it has been serviced before to check it again. I'll refer to your suggestions and appreciate the help.

Cool let us know how it goes, ask the shop if the exhaust valves have ever been replaced. On the pre 2006 model year 4tec engines they had an issue with the exhaust valves breaking. Basically the vavles are hollow, and with them being exposed to 100% humidity because of the water trapped in the exhaust system (waterbox etc) they would essentially rot then break and cause all kinds of damage. Not trying to scare you away from your new boat, just a few things to keep in mind.
 
Status
Not open for further replies.
Back
Top