"Have an older 470 that was re
"Have an older 470 that was rebuilt a year and a half ago and all seals were replaced. Also told the shop to replace any hoses that were suspect. Now the problem:
Started the boat this morning, she fired right up, and as I was idling out of the marina the temp got up to 220 degrees. Threw it in neutral and revved the engine a bit, figuring I had an air lock, but the temp didnt come down so I shut the engine off. Cracked the rad cap and let the steam vent, then added about 5 quarts of water. A couple days previous my repair guy was making some adjustments to the positioning of the 4 inch ehat exhanger so I figured maybe some coolant drained out and he didnt replace it. When the engine was topped up with water, the temp came down to 140 degrees and I ran the boat for about 80 mins at cruise spped (3600 rpm and 22.5 knots). Stopped to fish, used the kicker, then fired up the big engine for 20 mins to relocate... no problem.
A couple hours later decided to call it a day, fired up the 470 and ran 3/4 of the way home, engine temp around 140-150, normal. Got a phone call, so stopped the boat and put her in neutral, and within a couple minutes the temp was back up to 220. Shut the engine down again, added another 5 ot 6 quarts of water, and then ran the rest of the way home no problems. Even cranked the rpm up to 4000 and speed to 26 knots and the temp held at 140 degrees. Refuelled the boat, and when idling back into the marina the temp started to climb again, got to 160 by the time I was back in the slip. The engine needed another couple of quarts of water.
So where is the engine coolant/water going? I couldn't see anything in the bilge, and why only at low RPM? Why not at cruise speed? Anyone have any thoughts or ran into this problem before?
In the next couple of days my marine repair shop is going to go down and do a pressure test, but I am starting to lose faith in these guys... seems they fix on problem to have it replaced by another!"
"Have an older 470 that was rebuilt a year and a half ago and all seals were replaced. Also told the shop to replace any hoses that were suspect. Now the problem:
Started the boat this morning, she fired right up, and as I was idling out of the marina the temp got up to 220 degrees. Threw it in neutral and revved the engine a bit, figuring I had an air lock, but the temp didnt come down so I shut the engine off. Cracked the rad cap and let the steam vent, then added about 5 quarts of water. A couple days previous my repair guy was making some adjustments to the positioning of the 4 inch ehat exhanger so I figured maybe some coolant drained out and he didnt replace it. When the engine was topped up with water, the temp came down to 140 degrees and I ran the boat for about 80 mins at cruise spped (3600 rpm and 22.5 knots). Stopped to fish, used the kicker, then fired up the big engine for 20 mins to relocate... no problem.
A couple hours later decided to call it a day, fired up the 470 and ran 3/4 of the way home, engine temp around 140-150, normal. Got a phone call, so stopped the boat and put her in neutral, and within a couple minutes the temp was back up to 220. Shut the engine down again, added another 5 ot 6 quarts of water, and then ran the rest of the way home no problems. Even cranked the rpm up to 4000 and speed to 26 knots and the temp held at 140 degrees. Refuelled the boat, and when idling back into the marina the temp started to climb again, got to 160 by the time I was back in the slip. The engine needed another couple of quarts of water.
So where is the engine coolant/water going? I couldn't see anything in the bilge, and why only at low RPM? Why not at cruise speed? Anyone have any thoughts or ran into this problem before?
In the next couple of days my marine repair shop is going to go down and do a pressure test, but I am starting to lose faith in these guys... seems they fix on problem to have it replaced by another!"
