twin outboards

[Birdnest]

Okay you salty dogs,

How many of you run twins?

I want to put a 20-22' aluminum family/fishing boat together. Something like a cuddy with an alaskan bulkhead. It would be used in the San Juans mainly. I was thinking instead of a say 90 hp Honda 4 stroke, twin 40/50's Honda 4 stroke. The main motivation is redudancy and that it looks real cool. :grin:

Would a guy plumb them to sepate fuel cells for added protection? Could you troll with out a kicker? Would this increase/decrease your fuel consumption? Is weight an issue? Other than two of everything maintaing your outboards, what would be the disadvantages?

BTW, when you guys make your roadtrip to Ed Wing, it would be real nice if you could post some pics.

Fish me,

Birdnest

[Chaps]

I troll fine with my single Honda 90 and it's rock solid so going with twins for redundency is not worth the addt'l maintenance hassles and weight on the transom IMO. What you should have are two batteries and two fuel tanks with separate, cascading filtration (course>medium>fine) and water separation. On the Honda's, (and probably most other newer o/b's) as long as you have power to crank them and super clean fuel they will never let you down.

For trolling with a bigger 4 stroke it's easy to add a micrometer style throttle adjuster. I put one on and can vary the speed in 10 rpm increments. Next time you are over on the west side of the sound stop buy and I'll show you how it's rigged - Bob

[edsr]

Mugwump - Noticed your post about 90 Hp Honda and being able to make fine adjustments. I am running a 90 Hp and do use it for trolling but It seems that 1150 rpm is as slow as it will idle when trolling. Is it possible to control your motor to a slower speed than the base 1150 that my motor runs? If so I would be interested to hear how you did this and what parts are necessary.

[Rod Holder]

Birdnest, this issue has been analyized to death on on other internet bulliten boards and it boils down to being about a wash as far as maintenance, weight, fuel consumption and the cost of twins VS a large main + kicker. So the bottom line is do what ever makes you happy. I run twin honda 40's, I like the security of having two engines, each with the ability to get me home. I also get a bit more manuverability for docking with the twins + it looks cool....my $0.02

[Chaps]

edsr,

Are you saying that your motor idles at 1150? That is pretty fast, factory setting is about 700. I'm assuming that what you mean is that as soon as you begin to push the throttle forward the engine jumps up to 1150 . . . right? This is typically the problem . . . in gear at idle the trolling speed is too slow but as soon as you knudge the throttle forward the speed is too fast. This is mainly due to the main engine controller not being able to accurately respond to small adjustments being made by the operator.

The solution is to control the throttle linkage on the carbs independently from the main control. This can be done with another throttle cable called a "vernier" type. These are used on engines where the operator wants to adjust engine speeds precisely (like fire pumps, agricultural equipment, etc.)

Instead of a lever that moves the cable the vernier type uses a twist knob that lengthens or shortens the control cable in very small amounts as you turn the knob. See pic:

knob close-up:


Once installed, about every quarter turn of the knob will gain (or reduce) engine revs about 10-15 rpm which gives you super control over troll speed (your main control is left in it's idle position). The red button in the middle of the knob quickly returns the engine to idle rpm if you punch it. The trick is figuring out how to attach the cable to your carb linkage so that the system doesn't interfere with normal operations. On the BF90 I installed the cable so that it enters the engine cowling right alongside the main control cable. Once inside it wraps around the back of the engine and turns up into a vertical position next to the carb linkage. It is secured in this position by a simple bracket that I made from some brass strap mat'l that I got at the local hardware store from those metal displays (I really need to post a picture of this then all is obvious). Once you have the cable secured the internal wire (that gets pushed & pulled) is left long enough so that it can be bent over the top pin on the carb linkage in an inverted "U" shape. This way, if the main engine controller is used the linkage will operate unhindered because the travel is towards the open end of the "U". When the vernier controller is used the "U" pulls down on the linkage and slowly opens the carbs just enough to give you the precise control you want.

Whew! Anyway, if that is at all clearer than mud then great, otherwise I'll try to post a pic of the install. I've got my initial idle set at about 550 and depending on wind, currents, type of terminal gear, etc I can adjust the motor to anything between 600-1400 rpm to get the desired speed. I also run a lower pitch prop that makes everything work even better and I really didn't notice any loss of cruise speed from doing that.

It's pretty easy to do, I think the parts cost about 60 bucks and it totally eliminates the need for a kicker so if you have a 4 stroke main engine its a good way to go cause they will run all day at troll speeds and never complain (or use much fuel)

The vernier cables can be bought in long enough lengths so you can mount the knob at your helm. I found them at a site: throttle cables but you can find them locally at heavy trucker parts houses, etc. I used the 4100 series if you go to the site.

uhh . . . rather long winded answer but hope this helps . . . Bob

[ 01-17-2003, 09:34 PM: Message edited by: Mugwump ]