How does a "Trolling Valve" work?

[BigGrin]

Looking at a 02 or 03 Mack w/315 Yanmar and was wondering if this boat will slow down enough to troll well. I have heard of a "Trolling Valve" that goes on a diesel engine but know nothing about this device. Any comments would be appreciated. BigGrin :lol: :D

[Leprechaun]

Though I have never owned one, I know it internally shunts hydraulic fluid around the clutch packs instead of to them, thus cutting the torque supplied to the prop.

It cannot be used at higer than idle speed because it could starve the clutches of needed lubrication and though like I have said, I have not seen one, I would think that for what they get for them they should include some sort of an idle speed lock-out that would prevent you from pushing up the throttle when the T/R is engaged.

I would hope so anyway.

rgds, Leprechaun

[DBM]

My father runs a 40' MDI downeastern with a Mack diesel and a trolling gear. While he does troll, he mainly uses it for close in manuevering because he has a monster prop that at idle pushes him around at 6 knots.

I don't know how it works but I do know it works well. I also know it wasn't cheap.

I trolled my 20' for the first time this weekend and I couldn't go much less than 3.5 knots into the current and 4.5 knot with the current. I'm not sure this was too fast, as I've never trolled on a boat w/ a GPS before, although it did feel a little fast. I even tried throwing a 5 Gal bucket over the side but I only reduced my speed by 1/2 knot. I also didn't get even a bite.

Good luck on your decision and you can't go wrong with a Shamrock.


Fair seas,

DBM

[Brian]

Lep is correct - when the trolling valve is opened - it cuts down on the oil to the clutch in the trans and allows the clutch packs to "slip". The control for the unit is "variable" - you could slow down enough to count the revolutions of the shaft. The only problem that I have encountered with the trolling valve on my ZF trans is that when the oil is hot, the valve is very, very sensitive. I basically have a manual control on my helm station (similar to a manual choke on an older car). The difference of trolling at 4 knots and 2.5 knots is microscopic at times (how far out the control is pulled) but other than that - it works very well. You should also know that if the boat is taken out of gear, the valve has to be closed and reset (not a problem - you just push the control in and pull it out until the desired speed is attained).

Brian

[Leprechaun]

Though I have never owned one, I know it internally shunts hydraulic fluid around the clutch packs instead of to them, thus cutting the torque supplied to the prop.

It cannot be used at higer than idle speed because it could starve the clutches of needed lubrication and though like I have said, I have not seen one, I would think that for what they get for them they should include some sort of an idle speed lock-out that would prevent you from pushing up the throttle when the T/V is engaged.

I would hope so anyway.

rgds, Leprechaun

[Prior Engagement]

DBM - If you are trolling for Trophy Stripers like I think you are, you are going too fast. 2-3 knots would be a lot better. Don't know what to tell ya to do. Maybe a drift/sea anchor or two buckets, but I really think you need to slow down to get a better bait presentation for Stripers. Wiring lining for Flounder requires a really slow troll too.

BTW - I don't know squat about trolling valves except that they are a little pricey $$.

[SSJULZ]

Have you tried putting your trim tabs all the down? The extra drag will slow you down a little more.

[DBM]

I didn't try the tim tabs because in the A.M. when I was out, seas were running 2-3' and I didn't want to drive the bow down into it too much.

Thanks for the advice though.

DBM

P.S.- Can you guys who know your engine give me instuctions on how to turn my idle down. I currently idle at around 700 rpm's. Some time ago some good soul on the site gave me good instructions but I can't seem to find the old post.

[BigGrin]

Thanks for all the feedback. I wonder though if the Mack w/Yanmar will troll well (for Stripers in the bay) without a "Troll Valve" or I guess it will be a bucket or two out back BigGrin :D :wink: .