Repettive Idle Operation

[Sea Rider]

Scenario :

Small marine facility

310 Rib shuttle transporting boaters from pier to moored boats and viceverse.

Tohatsu 2 strokes 18 HP engine

Distance : 50 meters at the most

Water conditions : flat calm waters till noon, choppy then after

Fuel/Gas ratio 50:1

A rib/engine combo for tender use will be used repetitively at non planing speeds mainly because it’s small size, passenger load & short distance, was wondering if lowering the fule/oil ratio to 60:1 would benefit the plugs from fouling and engine smoking much less than operating at normal 50 :1 ratio ?

Assume that with 60:1 safe ratio will still be able to plane the rib in morning flat calm waters with just driver and copilot, going full wot for quick plane and then back down to ? to ? throttle to maintain plane for some minutes and plugs free of fouling untill next repetitive idle operaqtion is required. Thoughts, experiences are welcome.

Happy Boating

 

[pvanv]

Re: Constant Idle Operation

Re: Constant Idle Operation

Luis, if available, you might be able to run one of the newer "super" oils (such as made by amsoil) that can operate at 100:1. I would still run a little extra oil, say 75:1, and don't pound on the motor when running that low an oil mix. Less oil = less smoke, but some people really object to the aroma from amsoil Saber Professional 2-stroke smoke, even though there's less of it.

 

[Sea Rider]

Re: Constant Idle Operation

Re: Constant Idle Operation

Paul,

We usually use imported Yamaha, Amalie, Chevron TCW-3 2 stroke oils. Amsol super oil isn't available and probably more expensive. When refueling generally it's done using a 5 Gal container and pouring 5 oil measurements to be (50:1) would you say pouring only 4 measurements instead of 5 will provide sufficient lubrication for going wot to plane faster rib and backing throttle to 1/2-3/4 to maintain plane.

Besides sitting a mate as a bow mask for the bow to go down fast, you need at least 3/4 throttle to plane that small sib with an 18 at back, If throttling less will be constantly skyrocketing, worst on choppy conditions and against wind. So must take advantage of the flat calm morning sea conditions to plane both ribs and maintain free fouling spark conditions after extended idle speed use.

Happy Boating

 

[pvanv]

Re: Constant Idle Operation

Re: Constant Idle Operation

No, Luis, I'm saying that the super oils can run at leaner mixes. Regular TCW-3 probably can't. Yes, the super synthetics cost more. That extra price is usually offset by using less oil.

 

[Sea Rider]

Re: Constant Idle Operation

Re: Constant Idle Operation

Plainly understood needing less super oil. So, you wouldn't recommend using standard TCW-3 (4) oil measures in 5 gallons of fuel for the idle/wot operation described before ? What fuel/gas ratio would be running 4 oil measures mixed into 5 gal of fuel ?

Happy Boating

 

[sean mathews]

Re: Constant Idle Operation

Re: Constant Idle Operation

i would opt for a hotter spark plugs before i started leaning the fuel oil mixture

 

[Sea Rider]

Re: Constant Idle Operation

Re: Constant Idle Operation

i would opt for a hotter spark plugs before i started leaning the fuel oil mixture

What would be the tech benefit of doing so ?

Happy Boating

 

[sean mathews]

Re: Repettive Idle Operation

the hotter heat range plug would be less likely to foul at the low speed operation.