Engine Back in, Bunch of new parts.. First sea trial today. Running rich with a knock

[BajabossJD]

Hey guys,

Finally got the 7.4 back in the Baja and up and running. New Coupler, new starter,New Gimbal Bearing, New Belts, New hoses, new gaskets on Manifolds, New Oil pressure sender, Rebuilt my Weber 4 Barrel Carb too..

Rebuilt carb with the Edelbrock kit (read it was the same). Carb was so choked up, one bowl was filled with nasty grime. Cleaned it all up, replaced the items in the kit. Installed on boat. Fired up, but running rich. Played with the mixture screws and they do nothing (port side screw does very little, Star screw does nothing). Turned them all the way in and still very rich. Creating hard starting, lots of smoke. Engine runs stronger than ever. Shoots to plane... 4500rpm..60mph. Did a WOT run (about 1 minute).. Did it again and started hearing something unusual.

I heard a knock from somewhere. I left the hatch off so I could check everything out. I dont hear it at Idle or under 1100 rpms. Drive up or down I hear it, but I dont know where its coming from. New Oil sender says 20-40psi when hot..never dropped below that. I left the timing where it was when I did all this work, and didnt touch the CAP or rotor... could be overtimed? I have junk gas in the tank. had 10 gallons of bad, mixed with 10 of good and just wanted to burn it out (didnt smoke like this before I did the rebuild..it was dripping out of star primary jet and that was all) Now I dont see it shooting out at all at idle, just some fuel toward the left back side in a valley, left of the secondary jet.

I fired it up on the trailer and took a video for you guys to listen. I think I hear it in the bottom part of the bay (starter is loose and needs to be shimmed..sounds rough when starting, but I dont think it plays a part after the engine is running)

I moved the drive up and I think it got louder and a little rougher ( I did grease the U joints with Marine Grease when it was off..they wernt firm, but they had no movement,wiggle or noises).

Spent 2 months and $$$ on this..please tell me its not a bent rod, or spun bearing. Oil Pressure doesnt drop and can't hear it below 1100rpm..

This is 1800 rpm, neutral. Also..Alternator is whining..ordered a new one of those on Friday. Do Bearings In Alt sound like this when bad?

(the diesel sounding noise)

Thanks,
Joe

 

[NHGuy]

Re: Engine Back in, Bunch of new parts.. First sea trial today. Running rich with a k

Since it's a smoky mess and the idle mix screws do nothing you need to recheck your parts against your carb info. Also, if you are running the carb at greater than idle opening the idle mix screws do little or nothing. What is the idle rpm? Did you completely dissasemble and dip the carburetor, then make sure all the openings were perfectly clear? The spray stuff isn't enough for what you are doing. If the carb was completely cleaned it sounds as if the idle screws are wrong, is that possible?
As to the noises. Get rid of the ones you know about then recheck. Get the starter shimmed and tight.
To listen to the alternator you can carefully listen with a mechanics stethoscope from you local parts store. You can also remove the belt and spin the alternator by hand to feel and listen to it.
After that stuff see if the bigger rattle is there. It's pretty hard to find what might be noise #3 if it turns out to be part of noise #1 or noise #2. Don't chase your tail, do it the easist way.

 

[BajabossJD]

Re: Engine Back in, Bunch of new parts.. First sea trial today. Running rich with a k

Thanks for your response. Yes, took the carb apart. Soaked it in Acetone all night. Cleaned all passages, replaced gaskets and o rings. All jets were working fine. Idle rpm is 700ish. Screws still do nothing. I replaced the needle valves and adjusted the floats per kit. I changed the metering springs with the ones in the new kit (they looked the same). I'm getting smoke throughout the whole RPM range, but it runs really good.

Thanks,
Joe

 

[NHGuy]

Re: Engine Back in, Bunch of new parts.. First sea trial today. Running rich with a k

Do you still have the old needles? Compare them. Did the kit you installed change the idle jets or seats? And if so did they get left out or done wrong? Your idle is low enough, is the timing to spec? I know you didn't move it, but it should be verified or corrected.
Change the fuel filter repeatedly, dump the contents each time into a clear jar. Eventually it will come out clean.
Maybe the smoke is from the rotten fuel. But you still need to be able to adjust the needles for a smooth smoke free i

 

[RareVee]

Re: Engine Back in, Bunch of new parts.. First sea trial today. Running rich with a k

I would remove the engine belts to eliminate any possibilities there such as P/S pump, etc. If it knocks like that still then you need to remove your engine oil filter and cut it open. Once the filtering cartridge is out of the metal canister housing then make a slice up and down thru the element and pull it away from the supporting core so that only the felt element is left in one big long accordion looking piece. Cut off at least 1/4 of it and put the folds back together. Squeeze the folds together in a vice and this is disperse all the engine oil and leave anything else behind. Look at the element for signs of metal and what type/color if any. This would be my next step if the belt removal yielded nothing.

 

[BajabossJD]

Re: Engine Back in, Bunch of new parts.. First sea trial today. Running rich with a k

The needles looked the same on the kit. Different color..thinking the original ones were red/orange..new ones may be blue..but looked the same. Used same jets. Took air horn off, only one bowl is filling ( port side). Other side completely dry. Lots of black smoke.

 

[Bondo]

Re: Engine Back in, Bunch of new parts.. First sea trial today. Running rich with a k

Carb was so choked up, one bowl was filled with nasty grime.

The needles looked the same on the kit. Different color..thinking the original ones were red/orange..new ones may be blue..but looked the same. Used same jets. Took air horn off, only one bowl is filling ( port side). Other side completely dry. Lots of black smoke.

Ayuh,.... Obviously, the carb rebuild was a failure,...

Ya need to try again, or replace it...

 

[BajabossJD]

Re: Engine Back in, Bunch of new parts.. First sea trial today. Running rich with a k

Shimmed starter, it engaged better but still not great. The bolts are TIGHT.

Took carb apart again, blew out crossover tube (fuel line in air horn)..adjusted floats lower. Took Alternator out of the belt loop.

Started first try..no smoke...no flooding, but still heard a knocking sound above 1300rpm.

Checked oil..Gas smell. Drained 8 quarts of oil gas mix out (didnt see any metal in oil). Put fresh 40W in with new filter. . New gas in gas tank now.

Tried to start again, starter slipping...(Junk DB ELECTRICAL starter..should have known for $59). Didnt even bother trying again (dont want to mess up flywheel..I felt and didnt feel any chips)

Ordering a good quality starter now. I hope that thinned gassy oil was what was causing the noises. Hopefully it goes away with the fresh oil. I took it easy on the engine when I started hearing that knocking..went about a mile or two during that sea trial.

No doubt the gas was from the carb dumping bad fuel into the engine..

Thanks,

Joe

 

[NHGuy]

Re: Engine Back in, Bunch of new parts.. First sea trial today. Running rich with a k

Boy, you sure are getting a beating. I hope you are right and it's only the carb. Make sure to check the oil after a little running, then a little longer run, then a good long run with some bigger throttle openings.
Call DB they have a help line that might be able to answer your starter problem.

 

[Silvertip]

Re: Engine Back in, Bunch of new parts.. First sea trial today. Running rich with a k

Call me curious, but how do you rebuild an engine without disturbing the distributor. Regardless what you did, timing is called for.

 

[mr 88]

Re: Engine Back in, Bunch of new parts.. First sea trial today. Running rich with a k

Let me guess,you are buying another automotive starter for a marine application. Unless you do not like to live,buy a marine starter.They need to be shielded properly or boom goes the boat after a fill up.Do not go cheap on the starter unless you like removing and installing them or you have tow usa insurance.He OP never said he rebuilt the engine,just put some gaskets etc on it.WAS it rebuilt from the crank up Mr. OP ? Rod knock comes to mind after listening to video.Gas in oil is not good,unless it all came from your carb "rebuild" issues as you noted. Old crappy ethanol gas translates into crappy fuel lines, if any are rubber,the small chunks deteriorating will continue to plug up the carb.

 

[BajabossJD]

Re: Engine Back in, Bunch of new parts.. First sea trial today. Running rich with a k

Correct, I didn't rebuild the engine. Pulled it to change coupler. I'll get a marine starter on it and let you know. Never had gas in oil before the carb rebuild. As noted, it started fine with no smoke and no more flooding in carb.

Been a miserable project.

 

[mr 88]

Re: Engine Back in, Bunch of new parts.. First sea trial today. Running rich with a k

Well I would do a compression test to see what I have to work with before going any further.A knock that speeds up with rpm's is usually internal,unless you have something hitting the coupler,which is something you replaced. A mechanic's stethescope will help pinpoint the source.

 

[Glaspar_Fan]

Re: Engine Back in, Bunch of new parts.. First sea trial today. Running rich with a k

Use a two or three foot long hose to isolate where the knocking is coming from. I was convinced I had a bad backfire in my exaust or severe detonation when I first got my (25 year old) Searay. After taking the time to isolate the noise, it was definitely in the exhaust and seemed loudest at the rear. Turned out is was the flapper valves (drawing a blank on what they are really called) which had worn through their rubber coating and were flapping on the aluminum exhaust tube.

If you still have trouble with your carb, take it to a rebuilder. It's amazing what a difference a shop specializing in carbs can make.

John

 

[BajabossJD]

Re: Engine Back in, Bunch of new parts.. First sea trial today. Running rich with a k

Hey guys,

I pulled the drive off, reshimmed the starter (outboard bolt).

Fired first click and heard the noise again.. I thought it was coming from the coupler, so I took the drive off. Fired it up again, noise still there.

Took the water pump out of the mix for 10 seconds too.. Noise still there. Almost sounds like its coming from the top end, by the carb. The carb was very cold to the touch and I heard clicking/ knocking after I turned it off by the carb/ Valve cover.

I took plug wires off one by one and the noise never changed or went away.

Listen to it change as I adjust the mixture screws (they work perfect now).

Thanks,
Joe

 

[BajabossJD]

Re: Engine Back in, Bunch of new parts.. First sea trial today. Running rich with a k

How about the timing tensioner? Is there one?
I hear this when the coil is disconnected. Still can hear a noise when turning over.

 

[Bondo]

Re: Engine Back in, Bunch of new parts.. First sea trial today. Running rich with a k

How about the timing tensioner? Is there one?
I hear this when the coil is disconnected. Still can hear a noise when turning over.

Nope,... Have ya done the compression test Mr88 mentioned,..??

Sounds more like a huff, or puff, than a knock to me...

 

[BajabossJD]

Re: Engine Back in, Bunch of new parts.. First sea trial today. Running rich with a k

Nope,... Have ya done the compression test Mr88 mentioned,..??

Sounds more like a huff, or puff, than a knock to me...

Doing a comp test tomorrow. I'll post the results.

I did put new gaskets on exhaust and carb.. I'll check for those.

 

[NHGuy]

Re: Engine Back in, Bunch of new parts.. First sea trial today. Running rich with a k

Have you checked the exhaust flappers? My OE metal ones sounded like that when the silicon had been burned off the edges. I assume you have a y pipe from the lack of engine roar. Put a stethoscope on the upper part of the Y pipe just below the rubber sections, that is where the flaps are. Listen there.
Or pull the elbows and the rubber hoses below them to get a look at the flaps. When they are good they are coated with rubbery silicon. When bad they are just plain metal and they jingle against the pipe. The original old style is an oval shaped metal piece that pivots near the middle. The replacement ones are non rubber and completely different The revised ones bend in the center from the force of the exhaust.

 

[BajabossJD]

Re: Engine Back in, Bunch of new parts.. First sea trial today. Running rich with a k

Started the boat today. It fired first click of the key.

Pulled the plugs..Completly black, sooty..a mess. They are only 1 month old..used for an hour boat ride (THE last boat ride)

The engine still had they funny knocking sound. Use a stethoscope..couldnt pin point the noise. Wasn't the flappers (wish it was, thanks for having me check).

Did a compression test.. Ready..? 60psi on all cylinders. Each Cylinder was within 1 psi. I rented the gauge from Pep Boys. I made sure the fitting went in as far as it could go by hand. 60 psi.

Is that possible for them to all be that low and run like it did? Or start first click?

See the pic of the plug. Hurricane is on its way, so I screwed the plugs back in, put the charger on and covered it up nice and tight.

What do you think?
Thanks,
Joe