whats the OHMS range for a OMC temp guage

[bob johnson]

so I have a few temp gauges , a few tempos and a red OMC brand guage..... I didn't have a sender, so I bought one, and it reads 240-33ohms. Is that the proper range? On my last boat rebuild I apparently got the wrong sender as the readings the shop got for my motor were about 15 degrees lower than my guage is reading.... and it was verified with infared........ so my only guess is the sender I bought then, doesn't match the guage I bought.....

 

[alldodge]

The 240 to 33 is the North American standard and believe it is correct, your issue is probably an old gauge. There may also be an issue with the sender if it is something like Sierra (aftermarket), Have you tested the sender?

 

[Fed]

IR is good for comparisons but not so good for straight out temperature readings due to emissivity.
Paint your motor black & the shop temperature will go up.

 

[bob johnson]

don't know how to test the sender.... the sender on the motor that reads too high was a brand new BRP sender... and the guage was also brand new but it was another brand... cant remember the brand, but It was a name brand..... I actually bought two of each, as I have a temp sender and gauge for each head on my boats. I used the IR temp guage to check..Im not sure what the shop used....when they set it up on a dynamometer , they told me the torque the motor was putting out, and how it was running.....and they told me the temps was much lower than the readings on my gauges!....which was good, because they were running at 180.... actually I think it was 20 degrees difference...I was happy to hear the motor was actually running at 160 and not 180........ this sender I just bought looks like a BRP sender, but it isn't... it was only $9 new......the BRP sender is $45!..... but the OHMs are stamped on the sender......sooo I thought id ask



bob

 

[alldodge]

Could swap the sender to see if its the sender or the gauge

 

[bob johnson]

Could swap the sender to see if its the sender or the gauge

not too concerned with the big boats I have...since I know about the discrepancy... this new boat is for my son and I was just curious about fitting it to a matching gauge. the one big boat I have I bought new gauges and new senders....and they work fine it seems.... both the big boats use double temp senders........ it is likely the ones that are off are because of the gauges not matching the senders..... the senders are usually hard to find....BRP sells them..... so my guess is the gauge must be the oddball...........