NicksterFL
Seaman
- Joined
- Oct 29, 2014
- Messages
- 61
Hi Folks
First post here, but have read through many posts on this form for months!
Hi, I have a 1971 Mercruiser 3.0 that was overheating on plane. I have only owned the boat for 3 months so I know no prior history other than it sat for a year. When I got the boat, the first thing I did was replace the impeller (entire housing, gaskets, etc) and then also the thermostat (140 marine thermostat). We took the boat out and it ran fine for about 30-45 minutes. Then while on plane it began to overheat. I dropped down to idle or a little over, just to keep moving, and the temp dropped back down to normal. I got back on plane and temp creeped back up.
Brought the boat home and replaced the exhaust manifold and riser (they were pretty bad) with new ones and also had to replace the impeller again (the plastic tube was melted) and top housing had bubbles in the plastic. So I completely reinstalled a new one. Now, I have it all re-assembled and have it running with the outdrive in a barrel w/water, and the riser is hitting 152-164 with my IR gun at idle. I cannot put my hand on the riser for more than 1 or 2 seconds before it's too hot.
I also checked compression and all cylinders are between 150-160.
I don't want to drop the boat in the water and burn through another impeller kit.
thoughts??
First post here, but have read through many posts on this form for months!
Hi, I have a 1971 Mercruiser 3.0 that was overheating on plane. I have only owned the boat for 3 months so I know no prior history other than it sat for a year. When I got the boat, the first thing I did was replace the impeller (entire housing, gaskets, etc) and then also the thermostat (140 marine thermostat). We took the boat out and it ran fine for about 30-45 minutes. Then while on plane it began to overheat. I dropped down to idle or a little over, just to keep moving, and the temp dropped back down to normal. I got back on plane and temp creeped back up.
Brought the boat home and replaced the exhaust manifold and riser (they were pretty bad) with new ones and also had to replace the impeller again (the plastic tube was melted) and top housing had bubbles in the plastic. So I completely reinstalled a new one. Now, I have it all re-assembled and have it running with the outdrive in a barrel w/water, and the riser is hitting 152-164 with my IR gun at idle. I cannot put my hand on the riser for more than 1 or 2 seconds before it's too hot.
I also checked compression and all cylinders are between 150-160.
I don't want to drop the boat in the water and burn through another impeller kit.
thoughts??