20r71s ???'s

[losnbama]

edited...ive put off my own project to help a friend out...what ive found so far...core plug on cyl head asbly gone and has sucked up what looks like rubber gasket.bad deal i think.top plug is oil fouled,btm plug is carbon fouled,top wire hot with one plug and not the other,btm wire intermittent with the same(hot) plug and not the other...the upper bypass valve is capped off,the nipple on the intake mani is capped off...as per the diagrams shouldnt these 2 be connected??? havnt pulled the fly yet as the motor was running but not as it should.carb was cleaned by another friend but only cleaned. i sugg a carb kit a week ago when he asked just in question what i thought could be the problem.but now as i have the motor in hand its just a bit more than a carb kit...i know i need to pull the flywheel to check that intermit spark. also the oil hose from the lower crnk case to the top of the crank case is cracked at the lower nipple.what is the hoses function?...what do you guys think???

 

[kbait]

Re: 20r71s ???'s

Check compression. Check spark w/tester. Replace lube tube from powerhead base to upper bearing. Replace spark plugs/gap .030". If that's all good and it runs poorly, check fuel delivery.

 

[losnbama]

Re: 20r71s ???'s

Comp is 113psi on both cyl. Did the ole ground the plug test for the moment. Is the upper bypass nipple supposed to be connected to the intake manifold nipple? I know some motors used a pressure tank and utilized the intake nipple. But this one is capped and has a fuel pump as per the diagrams I've seen.

 

[losnbama]

Re: 20r71s ???'s

pulled the fly n guess what View attachment 120202 a burned point...the coils,condensers,and other breaker looks new...what would cause this burnt point??? also the top of the lower piston head is dry while the top is wet...no fuel to bottom cyl im sure,but why??? i think it has something to do with those plugged lines.?

 

[losnbama]

Re: 20r71s ???'s

put in a used set of points(cant get to my parts supplier today),reset points,reset coils,installed new oiler line.runs good...video link http://youtu.be/laMEUhxE3Kg

 

[losnbama]

Re: 20r71s ???'s

any ideas on the plugged lines in the video???????????

 

[garzilla]

Re: 20r71s ???'s

I have the 25 HP model....pretty sure upper hose ran to the manifold/carb area, if I'm not mistaken.....then another goes from cylinder, to cylinder (i think)
I can check when I get off.....btw, my folks just moved to Florence...near you somewhat?

 

[AlTn]

Re: 20r71s ???'s

if you'll go to marineengine.com and look at the diagram for the cylinder and crankcase..it shows 2 hoses and may help you see where they are supposed to go

 

[losnbama]

Re: 20r71s ???'s

@garzilla florence is bout 2 1/2 hrs away. I've seen 2 diff vids that show the 2 connected. So I did that and seemed to smooth out nicely. Enough for me to find another leak. The fuel pump cover is cracked so gotta get one those put on. I would love to know the purpose of the lines being connected is. @AlTn that's what led me back to iboats. Marine engine is an awsome look up the PDF manual I use is a bit confusing to follow and seemed to not have the page referring to this line hook up.

 

[AlTn]

Re: 20r71s ???'s

I'll be around a '71 25 hp. tomorrow, most likely, and will check those lines as well

 

[garzilla]

Re: 20r71s ???'s

any ideas on the plugged lines in the video???????????

On my motor (72) the one that's plugged in your video, runs to the port below the carb....the fitting above the carb, near the roller for the timing plate, runs to the fitting waaaaay at the bottom of the block, near the fuel pump.

The two use different size barbs, I wound up baloney cutting the small hose, and stuffing it in the larger....topped with a dab of silicone.

 

[losnbama]

Re: 20r71s ???'s

i ended up using an 1/8" id fuel/oil line.heated the end going to the larger nipple(intake mani) then stretched it over with needle nose pliers.it really smoothed out the idle and response to wot plus made the low speed adjmnt much eaiser. the oiler line i figd out pretty quick.just didnt know what it was called.(newb) then i saw the stator plt slow to return to idle when the twist throttle is let off fast.and traced it to the linkage arm that adjusts the stator has extreme slack at the connection point below the lower cover.any way to take up this slack??? ive thot about putting a spring attatched to the stator somewhere to get it to return.but only if i have too.

 

[garzilla]

Re: 20r71s ???'s

My motor doesn't snap back to idle either... I wouldn't worry about a spring...just my opinion though.

Although, it would sound sweet warming it up at the dock....with a huge pair of stinger pipes coming out the back..lol, other fisherman wouldn't be too happy I bet!

 

[AlTn]

Re: 20r71s ???'s

sounds like you got the lines figured out...if you'll find the cyl. % crankcase diagram ..look at part no. 41, control lever pin, I had one partially sheared and it prevented the armature plate from responding quickly....just takes a couple of mintues to check

 

[losnbama]

Re: 20r71s ???'s

The pin is good thanks AlTn but the slot it fits into is worn. And now I'm havin trouble gettin the motor to a shiftable idle. I'm close,real close but just can't get it to stop spitting at very low rpm. The stator wobbles from front to back when running and may be the cause. But I'm no expert by any standard. Also the line between the intake and upper bypass cover has a small leak at the upper cover. Ima beef up that small nipple with some heat shrink so it will get a better seal with a clamp. Maybe that will help. I saw some 1/16 fuel line at. The parts house. Wonder if that's what I need instead. One thing I can't understand. Why would a 1/16 nipple be run to a 1/4 nipple?

 

[AlTn]

Re: 20r71s ???'s

using the search feature....armature plate wobbles....Joe Reeves describes a method of dealing with that....heat shrink to eliminate that vacuum leak sounds doable...nipple question the only guess I could hazard would be to increase suction at the 1/16" fitting

 

[losnbama]

Re: 20r71s ???'s

Well the guy took it to the river and said it idles gr8 but wot is sluggish like it was running on one cyl. And then after a min or 2 started firing on both cyl and took off. But then caught a stump and sheared the prop pin. Anyone know where a kit for the stator wobble would be?

 

[losnbama]

Re: 20r71s ???'s

FINALLY... guy took it out tuesday and ran it like a horse,and it smoothed out to his satisfaction...happy for him but i think ill be pinging in that ring when spring gets in full swing