Is it the Instrument or the Sender?

[bamaboy473]

We picked up a 10-year-old Chaparral and it passed it's maiden voyage flawlessly as far as drive system and a great stereo. What isn't working as new are some of the instruments.

They say Chaparral, so does anybody know what brand they are? Faria, Livorsi, ?? There is a CE on each instrument and the speedo and tach have Teleflex on them.

Luckily, the speedo, tach, oil pressure, temperature and fuel all seem to work pretty well, but here are the questions:

Trim Indicator reads full UP at all times. If a sender, then forget it....I know by how the boat's handling whether the trim is OK or needs adjusting. Does the gauge have adjustment?

VoltMeter reads 18 (pegged full right just like the Trim) I started the boat today on muffs and test the volts coming out of the alternator. Reading at the batteries was 13.48, so alternator is good, but meter reads 17-18, so is there a way to adjust the gauge to read more accurately?

VHF is inoperable, power to the panel and both fuses are good. Darned thing almost impossible to yank out, too.

The Water Heater had a check valve in-line that was broken and leaking. After checking every marine and plumbing store to no avail, I just installed a straight tube and eliminated the check valve, at least for the moment. Is there a big incentive to source another check valve?

Otherwise, a little stumble out of the hole that smooths out with full power applied. I'm tossing a bunch of chemistry into the tank when it gets below half full. We saw 46 with bimini and curtains deployed, so 48-49 is probably WOT and that's just fine for a 5.0L I/O.

At idle speed I'm seeing oil pressure around 30psi and at cruise around 45, with WOT of 4400 showing a bit higher on the Merc. Any comments on the psi numbers?

[VanW]

Usually when things are acting like that either the gauges are bad or there is a short or maybe loose connection in the wiring. Check the wiring first.

[TTaxi]

Not familiar with Chap gauges but if the tach and speed say Teleflex , it's like the rest of the gauges are part of that same model series. Teleflex made custom boat or engine brand specific model series that may not show in regular Teleflex catalog listings , but could usually be tracked down bythe numbers on the side of the gauges, not necessarily the CME's. The ones on my boat were made just for CrusaderEngines.

Unfortunately they sold their analog gauge division, so tracking down may be a bit more convoluted now. Call Teleflex if you remove the bad gauges and can discern model #'s and they should be able to aim you in the right direction. If you can contact Joe Federsel, he is very helpful .


Keep in mind that poor grounds and erroneus wiring repairs can cause strange gauge readings through unintended current paths including reverse depending on what is turned on.

The oil press. readings sound safe on the low side, but I suggest pulling the gauge sender from the engine and temporarily installing a mechanical O.P. gauge for a reality check. Of course mechanical gauges can be off also :-D . Make sure present sender & gauge connections are clean & tight at both ends for accurate resistance in the circuit.

[bamaboy473]

Good information, TTaxi, thanks. While tracing power to the VHF I noticed some rust on the nut and post for the ground buss, so the next clear day I'll remove, burnish and replace the ground connections.

The engine is amazingly clean for a 10 year old boat...looks like a year old and no corrosion or rust except on the mounts.

I'll get the numbers and call Teleflex in hopes that they'll be able to point me to a repair shop.

[GaugeThis]

Teleflex was bought by Vthree so you might want to give them a call. If the trim guages is pegged it usualy means the sender is bad or there is a bad ground. Hope that helps.