Hello -
We are at our wits end trying to solve this problem
DP SM 1.78 with TSK SX MHP Transom shield (2001) - replaced risers and manifolds in Nov, this spring among other things replaced bellows (both) and shift cable. On muffs and in water at idle temp is fine, then under load at about 2500 rpm - temp starts to rapidly climb. Checked raw water pump (volume test good), checked lines for blockage - everything clear. Installed clear tubing on suction line up to T-Stat housing and legs feeding manifolds - sure enough as the boat is put under load - starts sucking air, lots of bubbles. Also, at dock increasing RPM and changing trim, yields bubbles which might hint at the hose connection.
Have pulled the boat and going to drop the outdrive this week. I have searched a bunch of forums and folks have indicated that the tube to outdrive connection is the likely culprit. I'm working with a very experienced mechanic - most of his experience is with Merc's and old OMC's. Recently we back filled the raw water suction to look for leaks and the only water came out was at the nipple which apparently is equipped witha a drain hole. So hoping the brain trust can help point us to steps to ID the source of the air leak. Should we just swap out the nipple or are there other tricks or ideas which should consider?
Thank you for any insight folks can offer
We are at our wits end trying to solve this problem
DP SM 1.78 with TSK SX MHP Transom shield (2001) - replaced risers and manifolds in Nov, this spring among other things replaced bellows (both) and shift cable. On muffs and in water at idle temp is fine, then under load at about 2500 rpm - temp starts to rapidly climb. Checked raw water pump (volume test good), checked lines for blockage - everything clear. Installed clear tubing on suction line up to T-Stat housing and legs feeding manifolds - sure enough as the boat is put under load - starts sucking air, lots of bubbles. Also, at dock increasing RPM and changing trim, yields bubbles which might hint at the hose connection.
Have pulled the boat and going to drop the outdrive this week. I have searched a bunch of forums and folks have indicated that the tube to outdrive connection is the likely culprit. I'm working with a very experienced mechanic - most of his experience is with Merc's and old OMC's. Recently we back filled the raw water suction to look for leaks and the only water came out was at the nipple which apparently is equipped witha a drain hole. So hoping the brain trust can help point us to steps to ID the source of the air leak. Should we just swap out the nipple or are there other tricks or ideas which should consider?
Thank you for any insight folks can offer