Few questions. Setting carbs / New windows

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marklo154
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Few questions. Setting carbs / New windows

Post by marklo154 » Sun May 13, 2018 7:54 am

Hello Everyone,

Had a few questions

1) Looking to find out how to adjust or set my rochester quadra jet carburetor have a 270 crusader. I had bad gas, so I eliminated that, clean all the lines changed all the filter, and rebuilt the carb. When I was rebuilding the carb I found the plunder spring rubber seal was torn so this could be part of my problem. Both motors are running good however my problem engine still doesn't want to low idle. So I`m wondering if I should adjust the carburetor , however I would like to do it the correct way . My original issue has been the problem engine would not get up and go when I gave it throttle and would start backing firing, then after backing it off the engine would die and wouldn't want to fire back up, thus leaving me to come in on one engine.

2) Leaky windows- wondering if anyone has went to any other style or type of windows to replace there salon sliding windows. The reason I ask is the wood around the windows is pretty much rotten away and needs to be replaced.

I have never had good luck with this one engine
1978 Trojan F36 Tri Cabin

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Big D
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Re: Few questions. Setting carbs / New windows

Post by Big D » Sun May 13, 2018 9:34 am

Setting up the carb properly is definitely important but have you checked your timing and the condition of your distributor? If the advance mechanism is sticking, you'll get those symptoms too.
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marklo154
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Re: Few questions. Setting carbs / New windows

Post by marklo154 » Sun May 13, 2018 9:45 am

Timing and new distributor was addressed. Early last year. But we did use the boat much last year.
I guess i could chexk timing again i dont have experience doing so but with some advice im sure i could figure it out.
Basically i tired of paying to have this one motor looked at over and over again only to always say bad gas. Even after i take that out of the equation.
1978 Trojan F36 Tri Cabin

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prowlersfish
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Re: Few questions. Setting carbs / New windows

Post by prowlersfish » Sun May 13, 2018 10:13 am

My I ask how you eliminated "Bad gas" ?
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marklo154
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Re: Few questions. Setting carbs / New windows

Post by marklo154 » Sun May 13, 2018 10:49 am

I am running both motors off the one tank of the good engine.
I have cleaned and rebuilt the carbs. Changed all the filters and cleaned out the fuel lines.
1978 Trojan F36 Tri Cabin

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Re: Few questions. Setting carbs / New windows

Post by P-Dogg » Sun May 13, 2018 12:03 pm

For a half hour of labor and maybe some gaskets you could switch carbs between motors. If the problem moves to the other engine, it's not timing or ignition related.

As for adjusting the idle, what does the service manual that you followed while rebuilding the carb say? After you pressed out the idle jets to clean them while rebuilding, did you use music wire or the (undamaged) chuck end of a drill bit to verify that the constrictions at the lower end were still the specified size?

You may also want pull the top half of the carb off and peek into the float bowl. I thought that I did a very thorough job refreshing my fuel after it got water into it. Flushed lines until i got clear fuel, installed new filters, including water separating, and still had trouble, like you, at idle. Popped off top of carb to inspect and there was some water. Ran fine at WOT, but like singing, it's the low end soft stuff that is more challenging.
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marklo154
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Re: Few questions. Setting carbs / New windows

Post by marklo154 » Sun May 13, 2018 12:59 pm

I took your advise pdogg. I switch the carbs. And of course now both motors idle perfectly. No im very confused lol.
1978 Trojan F36 Tri Cabin

marklo154
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Re: Few questions. Setting carbs / New windows

Post by marklo154 » Sun May 13, 2018 1:04 pm

I spoke to soon lol. After running them at idle about 10 minutes. Now the prveiously good engine died and will not stay running at anything under 1000 rpm
1978 Trojan F36 Tri Cabin

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Re: Few questions. Setting carbs / New windows

Post by mikeandanne » Sun May 13, 2018 8:13 pm

marklo154 wrote:
Sun May 13, 2018 1:04 pm
I spoke to soon lol. After running them at idle about 10 minutes. Now the prveiously good engine died and will not stay running at anything under 1000 rpm
Old Carbs are very difficult to get right, sounds like you have identified the problem carb and it sounds like there might be something floating around in there. Now that said, sometimes with old stuff it is just better to replace with new, throttle shafts wear out,idle circuits get partially plugged,and the carb bodies get porous, just not worth the hours of fooling with them. Good luck, hope you find the issue.The backfiring is symptomatic of a lean condition, engine is looking for more fuel.
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Re: Few questions. Setting carbs / New windows

Post by mrjake56 » Mon May 14, 2018 4:51 am

The Chrysler Marine 318/360 service manual provides very detailed information on Rochester carburetors.

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oldboat1
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Re: Few questions. Setting carbs / New windows

Post by oldboat1 » Thu May 17, 2018 12:33 am

No expert, but the idle mixture screws down at the base of the carb might need adjustment. From soft seating, initial setting is 1 1/2 open (counter clockwise). Start the engine and warm it up, then bump the needles 1/8 turn clockwise (leaner) to find the smoothest idle. Surging means overly lean — move the needles c. clockwise about 1/8 turn and let it smooth out.

Small adjustments.
Motors should run. People -- not so much.

1980 F26, Mercruiser 305
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marklo154
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Re: Few questions. Setting carbs / New windows

Post by marklo154 » Thu May 17, 2018 8:04 pm

Update on my situation.
My neighbor at the marina has been giving me a hand this week to try and get thinking going with my motors here. Thought we had it but of course not.

Switch the carbs back to there respective engines and began to address the starboard motor ( problem motor ) . We started with some basics. Set idle mixing screws at carb to 1 1/2 turns out ( one was in all the way one was at 1 1/2 turns ), confirmed spark plug wires where in the right order according to the firing order, checked the timing, set distributor points. Increased idle screw on carb. With all this we had good success with both engines now idling and not dieing when being put in and out of gear.
So we take her out for a test run everything is going good we increase speed gradually and run for about ten minutes at 3000 rpm. Everything is good, sounds good no back firing where good. We slow down turn around to head back, increase speed starboard motor get up to 3000 rpm , port motor ( the good one ) now will not go above 2000 rpm, it just will not go, full throttle then back down an nothing tried a few times and nothing, no back firing or anything,



So we come back in now are at idle coming into the marina and lose one engine and then the other, they would fire back up but kept dieing throughout the whole docking process.
Few things I note : when the port motor wouldnt go above 2000 rpm smelled a good gas odour I assume from the exhaust from all the gas I was dumping in there .
Another thing when coming into the marina and docking and time I put either motor under load foward or reverse or even turned slightly while moving straight motors wanted to die.

Very strange and very confusing open to any suggestions or thinks to look at that anyone may suggest.
1978 Trojan F36 Tri Cabin

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oldboat1
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Re: Few questions. Setting carbs / New windows

Post by oldboat1 » Thu May 17, 2018 11:16 pm

A common element to both your motors is the fuel, as I understand it. You are running both from one tank after a fuel contamination problem in the other tank. I think I might start there, as you are now having issues with both motors. It’s possible you have a fuel issue in the current tank(?)

What about common fixes that you recently did to both motors. After switching carbs, did you adjust the carb on the good engine too? Any other changes to the good engine?

Guessing, of course. Has compression been checked on either or both of these engines?

(Feel your pain, btw. I’ve got to check the health of my old 305 — smooth runner, but not making rpms it should.)
Motors should run. People -- not so much.

1980 F26, Mercruiser 305
1979 14' Starcraft, 1957 18 hp Evinrude and '57 3hp Evinrude kicker

marklo154
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Re: Few questions. Setting carbs / New windows

Post by marklo154 » Fri May 18, 2018 6:10 am

I have not changed anything on the port engine ( the good one ) I did confirm the idle mixing screw positions and both where 1 1/2 turns out.

I did think back to the fuel again and I was thinking to pull it of that side or I may try to run the motor with some fresh gas of some 5 gallon tanks on the the back deck. I think this weekend I may pull the plugs see what shape they are in and well Im at it check the compression.
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oldboat1
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Re: Few questions. Setting carbs / New windows

Post by oldboat1 » Fri May 18, 2018 11:18 am

Think testing with a known fresh fuel source is a good idea. btw, Those carb settings (@1 1/2 open) are initial settings — could end up being the best setting, but usually a starting point to tweak the mix a bit. Engine should start and run at the initial setting, subject to further adjustment if needed.

I’m too old to be laying down or leaning down, reaching into the engine compartment — will have that done. Essential test, but kind of hate to get results — unless they are good! Hope you get good results.

Another “by the way” — might check the control linkages at the carbs to make sure there is no slipping or some other problem (Switching carbs and all.)
Motors should run. People -- not so much.

1980 F26, Mercruiser 305
1979 14' Starcraft, 1957 18 hp Evinrude and '57 3hp Evinrude kicker

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