engine temp guage / fuel guage

[Tom Glennon]

Gentlemen: Slowdance, 1987 #354 was launched this week and I have found a couple of problems with my guages.

This winter I rebuilt the raw water pump, and did the maintanance on the heat eexchanger while I was at it.  This weekend I fired up the engine, and it ran like new with a really strong flow of water out the exhaust from the rebuilt pump.... except the temp guage began to push 200 degrees, so I shut down and let it cool a while.  When I restarted, I opened the bleed valve at the thermostat to burp the system, which was sucessful, and the temp fell but then began to climb again.  I shut down again and replaced the thermostat, which seemed to cure that problem.  As the engine was running, I then checked all the hoses for any leaks on the water pump, and the heat exchanger; all was nice and dry.  Now I noticed the tach acting really erratic, so I shut down, and discovered the wire at the alternator was about to part, so I refitted a new connector and that solved the problem, but now my temperature guage is not working at all. Neither is the fuell guage.  Any suggestions out there?  I'm thinking I may need to replace the sending unit at the thermostat housing. I checked all the connections at the cockpit panel, and all seems secure, as was the wireing on the fuel tank.

Aside from these minor setbacks, I am looking forward to a great season!   

[Ron Hill]

Tom : Before you purchase & install a new temp sending unit - check the wire.  Take a separate wire and attach it to the + wire at the gage and then the other end at the sending unit - look for continuity.  If you have it, then the sender is bad.  Go to your Kubota dealer and get a new temp sender for a D950 engine in a B7200 tractor.

On the fuel gage check the ground first.  Then check the + for continuity.  If you need a new fuel sender see my Mainsheet article on the same subject. (Get a Tempo unit)   

[Tom Glennon]

Thanks Ron.... now why did I know you would have a good solution!!

I'll check things out when I get to the boat Friday, and post my solution hopefully on Tuesday.

[Mike Smith]

We launched Breezer yesterday morning, and did have one problem  The engine water temp gauge on my new Seward engine instrument panel rose to about 200+ degrees from the 160 I usually have, althought the high water temp light did not come on.  I had plenty of water in the exhaust - no steam, the impeller housing was cool and we could not find any spot on the engine reading more than 160 with a lazer thermometer.  We ran the engine in gear at 1800 RPM for about twenty minutes at the dock with no other signs of overheating.  We decided to get underway and had no overheating symptoms for the 20 miles or so back to my dock, other than the obviously incorrect temp guage reading.  I ran the engine at 2000 RPM (6.5 Kts) the entire way back to my dock (picture attached).  I have e-mailed Seward for a new sensing unit, but have not heard back from them yet.  Any diagnostic ideas?

Mike

[Rick Johnson]

If I have that same panel does it mean that my electrical system has been upgraded?  Does it also mean that the total hours on the engine is incorrect?  My C34 is a 1990 and the panel says it passed inspection in 1996...  Total hours when i bought her last year showed less then 500 hrs.

[Steve S.]

Hi guys, I have the opposite issue with my temp guage, it never reads above 140 F.  Is there some way to adjust the sending unit?  On my fuel guage, I put in a new tank with new sender and still cannot get the guage to work.  To be honest, when I pull the engine panel and look for wires it just looks like a rats nest to me.  Where does the grounding wire for the fuel guage go?  To the DC panel at the nav? 

[Tom Glennon]

This  weekend, having played around with many of the wires in the back of the panel, and replacing a few that looked suspect, the temp guage now comes up slowly, and reads at a steady 160 after running for a while.  All the hoses to and from the heat exchanger seem to be doing the proper cooling/exchanging.... and the engine is running perfect.  Now I just need to address the fuel guage (no reading) and all will be great!

[Doug]

I had similar issues with my '87: Temp & tach bounced or didn't work. Ditto for the fuel. Then the tack stopped alltogether.
Research here said to re-do the wiring harness to remove the plastic multi connector.  At first I didn't think I had them, and replaced the key/ switch. After that didn't work I cut away a ton of electrical tape I found the plastic connectors. Replaced them both, and all instruments work great.

Start with the basics.  Make sure the harness has been fixed. I know it looks hard, but it's not too bad. Other than getting access.

[Ron Hill]

Tom : If the grnd to the fuel gage is OK then you need to change out the sender/float unit and replace it with a Tempo unit.  Not surprising with the age of your boat.  I wrote a Mainsheet article on changing out the fuel sender.   

[Tom Glennon]

Thank you Ron.... The ground is intact on the tank, so I will put my "West Rewards" check to good use and get the new sender!

[Mike Smith]

Replacement engine temperature sensor arrived today and I swapped them out.  Now, as soon as the engine start switch is turned on, the low oil pressure light and alarm come on!  Oil level is OK. What next?  I'll start over again tomorrow morning tracing wiring...

Mike

[Bruce Hanson]

Mike
You did not mention if the light and buzzer remained on after engine start, if it did then the old adage applies: go back to the last thing that was worked on. If they stopped then it is once again a wonderful world.

[Mike Smith]

That's my standby - I put everything back like it was and have no alarms going off, but the engine temp guage creeps to between 180 - 240, same as before.  John Sheehan, Sea Shell, was kind enough to lend a hand testing circuits and found that on the Perkins M30 there is one oil pressure and two engine temp sensors - one sensor on the side of the engine operates the temp guage and the other on top of the engine sets off the high temp light.  I was installing the new sensor in the high temp light circuit instead of the temp guage circuit, which is understandable because they sent me a 1/2" sensor - I need a 3/8" sensor for the side of the engine.  So, another call to Seward... The drama continues...

Mike

[Gary]

I have noticed that our engine temperature gauge is voltage sensitive.  We have a 12v receptacle plug near the gauges and are able to watch voltage very precisely at the instrument panel.  The temperature gauge will rise with lower voltage up to 180 degrees (10-11.5v) and lower, 160 degrees when voltage rises (12-13.5).  I finally figured out we had dirty connections in the bus bar connector behind the instrument panel and the bus bar connector at the engine.  First tightening all screws in the bus connectors made the voltage very precise and consistant at the instrument panel.  The next job was to clean and retin each wire at the connector bars.  We now have very accurate instrument read out because of consistant voltage at the instruments.

[Mike Smith]

I was able to pull the temp sensor on the engine by using a deep socket ratchet wrench and extension via the engine access door in the head.  I didn't have to remove/move the alternator at all and lost just a little coolant.  Unfortunately, the diameter of the new sensor didn't match, so I've contacted TransAtlantic Diesel for the right sensor for the Teleflex gauge.  Seward only has the one size, which is strange. I re-installed the old sensor and ran the engne for a while - everything is as before, just high readings on the guage. 

For now, I'm moving on to the next project, which is installing Raytheon junction boxes for my instruments to avoid having to snake new cables through the all-too-narrow cable conduits.  Next, I plan to work up an additional 450AH battery bank (4 Trojan T105s) and locate it in the stern lazarette.  This should give me more than ample power for my Mermaid 5K BTU AC in the forepeak - which only draws 500 W - at anchor.  That way, I don't have to lug my Honda 2000 generator aboard and worry about CO poisoning.

Mike