FlowScan tach

[Paul45c]

Does anybody else have a problem with trying to get the Flowscan tach to read anywhere close to the right rpms? The rpms I care about most are in the 1900-2300 range, and I'm indicating more than 100 rpms higher than true at those speeds. That's the closest I can bring it with the switch settings on the head unit. Talked to Flowscan and they seem to feel that's just fine. I'm thinking it's not!

I've got 12v71s with the 37-tooth blower gear.

Like a lot of people on this forum, I could really care less about the FS, but it came with the boat so I figure I ought to make it work somehow.

 

[Ross Macdonald]

Paul..I have the same problem on our 60C. Same engines and same situation: they were on the boat when we bought it. Mine bounce around and drive me crazy. I do have analog tachs on the upper outside station so I just cross check the RPMs on that. The one thing that seems to be calibrated correctly is the fuel burn. For long range trips, it is invaluable. Not only actual fuel burn but total fuel used. Ross

 

[Paul45c]

I only briefly had a problem with a head unit readout jumping around, but pretty quickly traced that to a bad sender. There's no way a 12 cyl. fuel burn readout can be good news, so I'm solidly in the "hear no evil, see no evil..." camp where that goes!!

Thanks for the feedback. I'm just thinking that there's got to be some way to filter that reading and correct for it if FloScan won't. My last boat had digital Aetna Engineering tachs, and they were nice units. Though I didn't have them, I understand that you were able to order displays for them that cancelled out the 3% error from the sender.

Since my readings don't skip and fluctuate, I believe it must be a constant percentage error that leads to much higher absolute numbers at the higher rpms.

 

[captddis]

Funny, Usually I can only get them to read 100 rpm low. The problem is the blower gear ratio is like 1.95:1 or 2.05:1. The Floscan can only figure even ratio's. I believe someone on here found a way to get the correct reading using a different pulse generator.

 

[Paul45c]

That would be huge. Gee, you'd think FloScan would know that when you talk to them on the phone, though! Thanks, Dave.