Vaccum Gauge.-

[Sea Rider]

If in need to install a vaccum gauge on a 2 strokes single carb Tohatsu OB as there's nothing to connect it to. Will drilling a hole right in middle of intake maniforld and pressing a metal tube inside will work ? Would be cool to count with one to adjust idle's air/fuel mixture right on cue.

Happy Boating

 

[pvanv]

Use your ear. Simpler, cheaper, accurate. Then run the motor to check. A single-carb motor cannot have the idle mix adjusted by vacuum; that's reserved for synchronizing multiple-carb motors.

 

[Sea Rider]

Other issue,

On portable Tohatsu OB's, say 4-5-8-9.8 models, the starting procedure as per manual is as follows : Pull starter handle slowly untill you feel engagement, keep pulling till you feel less resistance, then pull it quickly. When doing so, find that sometimes both small metal ratches that engages against internal starter pulley assy slips off from dented pulley and end with an elongated starter rope. Need to perform the strating procedure once again.

Have bolted starter case around flywheel at different postions as there's some axial play to play with, did same. Assume the starter pulley assy has exact same bolts holes diam, that's with no axial play to play with, right ? So it's a off centered case issue ? BTW, OB has only 50 hours. When disassembled all was neat clean, not even grease around ratches as to blame for the slippage.

Was wondering if this slippage is quite normal, some sort of a flaw design and nothing to worry about. This issue doesn't occur on larger 15-40 HP-OB's with one ratchet recoil starting cases.

Happy Boating

 

[pvanv]

Check for wear on the ratchets, and check the starter pulley cup. If all is OK, install new return springs for the ratchets.

 

[ahicks]

Vacuum gauge on a 2 stroke engine will be pretty tricky. It would have to be mounted between the butterfly on the carb(s), and the reed valves, and then I'm not sure if it would provide you with a very good signal.

Usually you would only use a vacuum gauge when balancing more than one carb. A tach is more often used when adjusting idle mixture.

 

[Sea Rider]

With respect to ratchet and springs, ratchet has no wear of any kind whatsoever, spring makes ratchets to expand and retrieve flawlessly when assembly is removed, turned upside down and cord pulled slowly or vigorously. New springs are on its way. Moons back experienced same slippage issue on a rebadged Mariner M5B-OB.

It's just the mental bummer that something might break when cord is pulled and ratchet slips. For the moment will take my tools along a spare cord with me in case springs breaks when boating at far away distances.

BTW asked same question about installing a vacuum gauge on a 2 cylinder single carb to a motorcycle techie with a long career servicing motorcycles and other motors as well and said it will work fine. Moons back installed a vacuum gauge to a single carb WW Beatle drilled a hole right on middle of manifold much lower from carb base and inserted a 3m diam metal tube protruding 10 mm.. Read as a charm, my mechanic loved to fine tune my German beatle.

Saved me burning unnecesarry fuel by steeping to much on accelerator pedal, just stepping the necesarry to achieve an excellent fuel comsumption rate while burning less fuel.

A tach is only good to set idle rpm right once air/fuel mixture screw has been correctly adjusted and OB runs smooth and steady.

Happy Boating

 

[ahicks]

Pardon my lifetime of experience that would tell me that adjusting idle mixture can be done easily using a tach. And comparing anything in the way of vacuum done on a 4 stroke VW engine to something done on a 2 stroke, is another stroke of genius on your part.

Bottom line, if you aren't going to believe the answers you get, stop wasting others time asking them.

 

[Sea Rider]

Ahicks,

Paul is always right on his posts. For a well trained technician will surely be an out of this world crazy idea to install a vacuum gauge. By no means will go for one, just wanted a second opinion, my ears are sufficiently well trained to adjust air/fuel mixture on single carb engines spot on.

BTW, no one is wasting others time when posting topics, it's entirely up to you if wanting to respond or not, it's a open forum LOL!!

Happy Boating

 

[ahicks]

I replied to your request for help not knowing your mind was already closed on the issue. I don't mind giving somebody a hand, especially when it can save somebody learning something the hard way as I did. I do this with no expectations of any kind, though a thank you or a note saying the issue has been resolved and what they did to resolve it is nice.

What I do NOT appreciate is somebody that has little idea of what they don't know responding the way YOU did. If I had known you had no intention of carrying through with your vacuum line installation, trust me, I would not have responded. That's what I'm talking about when I say you've done nothing but waste other people's time. And worse still, is you don't see the issue I'm speaking of. What little respect I had for your opinions previously is now gone. It would be no surprise to find you were 12 years old....

 

[Sea Rider]

My personal experience was installing a vaccum gage on a VW Beatle, not on a 2 strokes single carbed OB. Period. Next time don't respond to my personal posts, worse if with agressive out of context answers. Besides, No One asked for your help!!

Happy Boating