Hynautic engine control fluid substitute

[Amberjack]

Hello all—up north in BC and need Hynautic engine control fluid. No one up here stocks it or even knows what it so I would have to fly it in. There are Hynautic systems all over so people must be using something as a substitute. Any ideas? This is the 50% glycol/50% waterfluid.

[Tony Meola]

Doug

Google Sir Craft Spruce. I forget the mil spec # but if you go on hynautics web site you can get it.

Even with shipping you should find it to be cheaper. SEA star used to list it as a dirddct replacement. For some reason now they sa y to use as a direct replacement it needs to be run through either s ffas goltef or coffee folter. Go figure.

[mike ohlstein]

Is this it?

https://www.seatechmarineproducts.com/h ... allon.html

[Bruce]

A 50/50 mix of Distilled water and a non additive ethylene glycol is the fluid. The trouble is finding antifreeze with no additives which can gum up the system.

[John C]

I used prestone advanced formula (yellow in color) a few years back and all is well. It has no leakstop or silicates in it. Make sure you get the right one there are several that have silicates. I bought their ( Hynautic) stuff about 10 years ago and when I went through the system during the winter of 15 it was a gummed up mess. Had to clean out and rebuild the senders and slaves. Controls have never worked better.

[Amberjack]

After fretting about it for a day I topped off the system with distilled water and headed north. Now we’re in Friday Harbor with 23 days and 415 miles on the clock, headed south and waiting out weather to cross the Straits of Juan de Fuca. The engine controls are probably 90% H2O/10% HA5455. That worked well enough to get us up to the Octopus Islands in B.C. original plan was to circumnavigate Sonora Island which involves several rapids with max currents running 9+ knots due to the full moon. No problem to transit anywhere near slack with a fully found B31 but there is enough residual current plus all the other boats trying to squeeze through at the same time make it chancy without responsive engine controls. I’ll tell the story of The two we did transit in another post. Throttle controls are clumsy and I’m concerned about lack of lubrication leading to failure so nursing home to complete the trip is the goal now. Once in the Straits I can notch in at 3800 rpm and not touch them until Seattle. Thank you all for the input and suggestions. In the end (like my ancestors sailing out of Boston) I improvised and it worked.

[Ripsangler]

I was told by the hynautic tech people to strain automotive antifreeze through double coffee filters if you are going to use it. I never had a problem with it.

[John C]

That is correct. Its in the service manual for the controls. I ran the prestone three times through a pack of paper filters ( very slow process) and got nothing. But as I stated you must use the stuff with no silicates in it.

[Amberjack]

So, back in homeport Seattle the first two marine supply stores I walked into had HA5455 in stock and on the shelf! I now truly appreciate the strong local marine industry I used to take for granted.

[Amberjack]

Those of you who followed my multi year saga of the starboard Hynautic throttle control will be interested to know the issue has been resolved.

Recap: that throttle control had all sorts of issues--spongy, throttle creep to lower rpm's which led to the 2018 debacle of bleeding the controls in BC and running out of Hynautic fluid to recharge the system. And then last year extreme reluctance to throttle up-- I really had to ram it to get the revs up, then they would tail down to 2500 and stay there. Made it challenging to run the BC rapids or join the parade through Dodd Narrows since I couldn't adjust rpm's reliably--if anyone suddenly throttled down I would have been sunk.

The throttle control valve set was replaced in late 2018, then the pilot check valve last spring and finally the charging block. I also dissembled the slave which looked clean and replaced the O-rings. No change. The only possible solution left was a blockage somewhere in that line.

When first purchased Amberjack had been configured for commercial trolling. The owner had added control stations in the salon and in the cockpit, with Hynautic lines running all over through the salon. When the cockpit was modernized the cockpit control station which was poorly done was removed and those lines spliced into a loop and left in place. The next owner could use them to reinstall the cockpit controls if wanted. I'm pretty sure that's where the blockage was--a low point with a brass union where the splice was probably corroded a bit and collected enough junk to form a blockage.

So a couple weeks ago I bypassed the salon and cockpit lines and ran a simple direct line from the bridge control 3' to the charging block, over to the slave, then up again to the bridge control eliminating about 80' of run for each control. We took the boat out last Thursday and it worked. Sweet, the throttle controls are light, responsive and AJ powered right up with no throttle creep! Plus I get to remove all the old Hynautic nylon lines running through the salon and tidy things up. When I install autopilot some day I'll get a simple remote so I can still drive the boat from inside if needed.

[Carl]

Great, I bet that was some relief....nice to be able to have control of the motors.

[Amberjack]

Carl it was like driving in rush hour traffic with a sticky gas pedal and a faulty brake cylinder. The constant low grade anxiety took a lot of the fun out of running the boat.

[Carl]

The constant low grade anxiety took a lot of the fun out of running the boat.

I bet it did...

Not sure if I'd have ventured out with my boat running like that. Glad you got it taken care of and can now use the boat with those crazy new-fangled gadgets know as working throttles.

[Amberjack]

Not sure if I'd have ventured out with my boat running like that

Perhaps I exaggerated slightly. (Does anyone on the forum ever exaggerate? No, never!!!).

Amberjack was reliable at idle so maneuvering around marinas was OK and stable at slow cruise, around 22 knots out in open water. The challenge came in the tidal passes where currents of 4-6 knots are not unusual and can range up to 9-10 knots if you miss your window and still decide to have a go. Add in a line of boats transiting at the same slack water and things could and did get complicated. We normally transit 3 of those passes to get up into our cruising grounds. So let's say hours of pleasant cruising with short periods of high anxiety. Almost normal cruising.

[Carl]

Perhaps I exaggerated slightly. (Does anyone on the forum ever exaggerate? No, never!!!).

Nope not me, I NEVER exaggerate. well maybe just that one time... but it was only a short story and only the one time, maybe twice but not more.