More on gauges After ordering an analog trim sender for my analog gauge, I set up the Smartcraft Monitor. I was using the trim and noted that the monitor automatically shows trim (1-25) to the tenth numerically. Pretty slick. Now I'm wondering why I have ordered a $40 analog trim sender to replace a $111.00 digital trim sender that works fine, particularly given the fact that I've invested in the Smartcraft Monitor. Based on DyneBob's advice, I put the Smartcraft Monitor front and center on the dash and it is very easy to see. Actually, the trim indication will let you put the trim right where you want it to a tenth of a point. You can't get that accurate with an analog gauge. If I don't use the Faria analog trim gauge, then what do I replace it with? I've got an Ammeter gauge that I'd rather not use, as I've heard bad things about Ammeter gauges and heat. I also have a Faria Hour Meter, but the Smartcraft already gives you the hours on the engine, so that would be redundant. I'm thinking about a Faria Cylinder Head Temp gauge. Jim - what do you think? Also - has anyone else used the digital trim indication from a Smartcraft Monitor and if so how do you like it compared to an analog gauge. I'm ending up with a lot of parts and gauges I won't need. I guess next time I do this I'll be better educated and spend less $$ on stuff I don't really need or want. MarkBano
Cylinder head temp is a good thing. I watch water pressure and head temp pretty closely. If you use the Smartcraft trim then a head temp is good. If you use analog trim the leave the Smartcraft set on engine temp. You do not need to monitor trim to the .1. I use the tach as an initial setting then monitor speed and adjust tach as required. I would swap the far left speedo with the tach to get the tach closer to the mirror for a good scan pattern. Your instrument panel is beautiful. I have gauges laying around too. jim
Perhaps I'll open a marine store... I removed the digital trim sender last evening to see how it works. I wanted to know if there would be a way to hook up both an analog sender and a digital sender at the same time. This does not appear to be possible. The sender operates off of a turning key that sticks out of the hydraulic shaft head on the power trim system. The key turns as the motor tilts. The key fits into the sender. There just is no reasonable way that I can see to duplicate that short of having 2 keys - one on either side, and the engine shaft assembly is not machined to include a second location for a trim sensor. So... it is either analog or digital. Take your pick. The reality of the situation is that the Smartcraft gauge could be the only thing on the panel and it would do far more than everything else I've got there. Unfortunately, the monitor is boring to look at and it doesn't give you the ability to "scan" various parameters at one time. So the question seems to be one of determining what information you want in an analog presentation to compliment the monitor. It isn't necessary to know your trim position to 1/10th of a point but if you find "sweet spots" for trim at certain speeds, then using the tach or speedo, plus the digital trim information, you could really "dial in" a setting for certain ski routines. All things considered, I think I prefer the digital readout. The analog gauges have hash marks but they are not very precise. The monitor can be set to automatically show the trim readout each time you hit the trim switch, so you don't need to cyle through modes with the mode switch on the monitor to get the information. (The monitor also shows you total engine time for a few seconds at start-up, which is nice. If I install a cylinder head temp gauge in place of the analog trim gauge, it will require installation of a temp sensor on a cylinder head. Then you're only getting cylinder head temp on one cylinder. I'm spoiled with the EDM 700 in the airplane that constantly monitors EGT and CHT on each cylinder all the time. Then again, that is a more critical application. My understanding is that the sensor for the marine gauge just bolts on to the head of a cylinder using one of the cylinder bolts to hold it on. Have you installed one of these, Jim? I'm not 100% sure yet whether I want to go with the analog trim gauge or the digital. I prefer the analog presentation but the digital is more precise. Probably not too many people have experience yet using the digital trim on a Smartcraft Monitor so it is hard to get feedback on this. Hopefully Bob will be on the water soon. He's got the digital trim on his boat.
I think Bob is going to hit the Fox this weekend at Boy Scout Island in St. Charles. I talked with him the other night. He was going to do a test run this last weekend, and the weather didn't cooperate. Greg
The trim on my boat is not that critical. If I want to go fast sometimes I pre set before I take off. The bow comes up a liitle trimmed like that but it settles down quickly if I am on it. That setting is good for about 25 to full speed. I have installed those head temp guages and sensors. You either need a spare wire in the bundle or run a new wire from the sender to the front. The water goes through the head pretty fast so I think it pretty much reads the whole head. You could use two senders and a switch for the gauge, or two gauges. I have seen both using a sender on each head. jim
I was too late to cancel the order on my analog trim sender so perhaps I'll just hook it up and see how I like it. I'll keep the digital sender in case I want to move the trim indication back over to the Smartcraft Monitor in the future. Jim - from what you are saying it sounds like a CHT sensor is essentially going to just tell you what the water temp is on whatever cylinder you've got the sensor attached to. Doesn't seem like this adds much to the water temp gauge. Am I right? On an aircraft engine, which is air cooled, the CHT would be limited to a particular cylinder, whereas the CHT on the boat engine would tell you what the water temp is at the head of the measured cylinder, which is the same water that is cycling through the system and which is already being monitored by the water temp probe. Am I missing something here? If the CHT gauge doesn't add much, I might as well leave the analog trim. The flip side of the digital trim issue is that if you use the analog trim gauge, you can select some other parameter to remain as the default parameter on the Smartcraft Monitor without interruptions from the trim numbers every time you hit the trim button. I don't know what you'd leave on the screen normally. I think the default is Tach but I'm not sure. Another interesting factoid from Mercury was the technician's comment that I should not splice into the pressure line for the shaft mounted pitot to hook up one of the speedometers. Recall that this line is hooked to a digital sensor for speed on the factory setup for a digital optimax. I wanted to splice with a "T" so that I can still get a speed reading on the digital monitor and on the mechanical speedo. However, the Merc. tech said that if I do this it will change the pressure differential and I won't get accurate readings on either the digital sensor or the mechanical speedo. He said to just disconnect the line from the digital and re-route it to the mechanical unit. My recollection is that you had studied this - Jim - and had concluded that splicing a pressure line to operate more than one speedo at one time should not change the accuracy of the speedometers. What do you make of the Merc tech's comments? Sorry if this is too much techno crap for everyone but, like Jim, I like this stuff. I've always had a theory that you can't be a really good pilot unless you absolutely have to know everything there is to know about every detail of the machine to the extent reasonably possible so I know a lot of pilots who dwell on this kind of stuff to the point of obsession! :smash:
To put it bluntly, I think the Merc mechanic is full of s--t. Pressure cannot escape out of the system. The added volume of the line to the front might add a little lag just like those brass tubes mounted on the transom that I can never remember the correct name for. But how much volume could there be in that tiny line? If you have any doubts, try it both ways. You have another speedometer to compare it with. That little research program should keep you out of the bars for a few days. The cylinder head temp measures a general overheat such as one caused by insufficient water flow etc. If one cylinder goes lean, it might show up a little. You need to be concerned with a clogged inlet or pump failure. You are going to get a warning at about 190*, but a pump that is warn from sand will show up gradually, and warn you that it needs to be replaced. jim
Jim they are "equalizer tubes" I love being able to tell YOU something. Thanks for easy pitch! 8) I agree with you, rather than the Merc tech who put me on hold to go get help each time I asked a question. I'm going to use a "t" and see what happens. Can't hurt. If it works, I can keep the speedo readout on the Smartcraft Monitor, which would be nice. I'm going to go ahead and use the analog trim gauge after all, at least for now. The mechanical representation might not be as precise as the digital, but it is more intuitive, when you are glancing at it quickly (a point my brother made during a conversation with him today on the subject). Also, I purposely placed it near the high speed speedometer so you can look at both quickly. Of course, now you want me to move that speedometer... :roll: Another interesting point - probably belongs in the prop thread - my brother got his new 19" Stiletto waterski prop today and the directions with the prop advise that he needs a different trim tab to allow for the rake of the prop. Doesn't sound like a prop that you'd like, Jim. The new trim tab shows up at $13.50 on Merc's Part's Express. I wonder if he should just remove the trim tab altogether... I don't think he's got any torque steer to speak of anyway.
I had that problem with a high rake prop. I just trimmed the trim tab. I would return the prop and get a Mercury Mirage in a 19 and have the cup removed. It will spin like a 17 then. jim
