rcon
New Member
- Jun 16, 2011
- 481
- Boat Info
- Preparation
'93 300 Sundancer
w/ Kohler genset
Raymarine E7D
- Engines
- 4.3l Mercruisers w/Alpha 1
First, the story and my apologies, it is a little long.
Just had new engine dropped in.
During sea trail with the mechanic, noticed new engine (port)was now reading significantly high (200F). We hand checked riser and t-stat housing, both appox 75C/165F (I make a lot of milk for coffee and know my 65C well :grin. At this point we suspect the new engine just reads "different" and this is to be the "new normal"
Ran her home for 3 hours, 20 min on the plan @3800RPM, then 10 min 2500-3000rpm as per recommendation from mechanic. Starboard ran at it's normal 160F-ish, starboard at 200ish (as per sea trail)
Fired up yesterday, and both gauges read off the chart, hard to the right.
Port (new engine), was quickly up to temp on both its riser and t-stat housing and all was well
Starboard, both risers and t-stat remained cool, then one riser started to get warm (but well less than 75c/165F), t-stat a little warm but nothing like the riser
Based on this we start 30 min out puttering around outside the marina in the 1000-2000rpm range so my old man could play.
Now, berthing was a little challenging as wind picked up, so I didn't get a chance to test this immediately, but approx 3-5 min after engine shutdown, the riser on starboard was, I would guess, at around 50C/120F, leading me to think it had started working as per normal.
One more thing (making me this I've got a short of some sort), 4-5 times during the trip, the new engine's oil pressure gauge would sharply drop to 0 and spring right back up to normal.
Now the story out of the way, some questions,
1. Is this hand testing of t-stat and risers a valid way to check operation of cooling system? (I'll be buying an IR temp gun today)
2. Is there likely to be any common link between temp senders, a short possibly?
3. With one riser much cooler than the other, I assume intake is one side, exhaust the other - correct?
As per above, let me see if I've got this right, water gets picked up thru my alpha one drive, pumped into intake riser, t-stat measures the temp of engine somehow (exhaust gasses? block?) then opens up and allows raw water to flow around the block, gets mixed with exhaust gasses and is expelled via the other riser thru the drive at the center of the prop. Temp sender unit runs from the block, not the t-stat housing. Have I got all that right?
Just had new engine dropped in.
During sea trail with the mechanic, noticed new engine (port)was now reading significantly high (200F). We hand checked riser and t-stat housing, both appox 75C/165F (I make a lot of milk for coffee and know my 65C well :grin. At this point we suspect the new engine just reads "different" and this is to be the "new normal"
Ran her home for 3 hours, 20 min on the plan @3800RPM, then 10 min 2500-3000rpm as per recommendation from mechanic. Starboard ran at it's normal 160F-ish, starboard at 200ish (as per sea trail)
Fired up yesterday, and both gauges read off the chart, hard to the right.
Port (new engine), was quickly up to temp on both its riser and t-stat housing and all was well
Starboard, both risers and t-stat remained cool, then one riser started to get warm (but well less than 75c/165F), t-stat a little warm but nothing like the riser
Based on this we start 30 min out puttering around outside the marina in the 1000-2000rpm range so my old man could play.
Now, berthing was a little challenging as wind picked up, so I didn't get a chance to test this immediately, but approx 3-5 min after engine shutdown, the riser on starboard was, I would guess, at around 50C/120F, leading me to think it had started working as per normal.
One more thing (making me this I've got a short of some sort), 4-5 times during the trip, the new engine's oil pressure gauge would sharply drop to 0 and spring right back up to normal.
Now the story out of the way, some questions,
1. Is this hand testing of t-stat and risers a valid way to check operation of cooling system? (I'll be buying an IR temp gun today)
2. Is there likely to be any common link between temp senders, a short possibly?
3. With one riser much cooler than the other, I assume intake is one side, exhaust the other - correct?
As per above, let me see if I've got this right, water gets picked up thru my alpha one drive, pumped into intake riser, t-stat measures the temp of engine somehow (exhaust gasses? block?) then opens up and allows raw water to flow around the block, gets mixed with exhaust gasses and is expelled via the other riser thru the drive at the center of the prop. Temp sender unit runs from the block, not the t-stat housing. Have I got all that right?