problem diagnosis

[hullofalottatrouble]

Dropped in a reman merc 260.. everything bolted into place.

got it started.. started and ran strong at around 900 rpm.. vacuum gauge read dead solid at 15.. little low but dead solid..

when i throttle back all the way it just died.. didnt run rough just died.. so figured it was an idle needle/screw adjustment.. or perhaps a throttle cable adjustment needed.. wasn't terribly concerned.. but had a therm housing leak so shut it down until got new gasket

all cyl are 150 dead on with compression test..

also wanted to tighten down the dist and swap out carb gasket in case slight vacuum leak there..

also pulled all plugs and cranked engine over to check for water .. fuel etc in cyl.. all good..

swapped out carb gasket and after getting carb back on - see other post - i bent the right idle mix needle on my rochester qjet...

i swapped the needle out with one i had in my old carb.. cleaned it off put it in..

put new gasket in therm.. put all plugs back in..

and started engine.. it ran terrible.. vacuum fluctuation from like 10-15.. sounded like cyl werent firing.. had to keep it at like 1200rpm to stay running.. checked to see if timing was way way off.. got it set dead on.. didnt help..

adjust left carb needle.. it had an impact on engine.. tried to adjust right carb needle.. it didnt do much..

the noticed smoke/steam rising from bottom of 2,4,6,8 exhaust manifold.. shut down engine.. manifold was super hot.. also had steam/vapor out of top of carb.. i checked manifoldd/riser before bolting on to reman and they were clear and thick walls.. new gaskets on them. and did not have overheat problems with them at end of last year.. also did not have overheat problem first time started reman engine before needle was bent...

didnt mess with it anymore.. comp test on 2,4,6,8 after all this was 150 dead on..

i am hoping all this is related to my bent carb needle and damage to seat..

but just wanted to check to see if doing this kinda of potential carb damage alone would result in such a terrible running condition.. i am guessing yes..

but before i went full steam ahead on trying fix carb wanted to make sure there wasnt something else i should look into..

thanks

 

[KRS]

Re: problem diagnosis

put plug wires back on correctly?

 

[hullofalottatrouble]

Re: problem diagnosis

krs.. good question and thats one of the first things i thought of too..

i double checked em what i put em back in and double checked em afterwards and they were correct..

it seemed like things just weren't firing correctly... but i checked and rechecked.. and they are good

 

[searay3]

Re: problem diagnosis

sounds like a pretty good vacuum leak. Those manifolds will glow if you hold the throttle open long enough. Make sure you have the right mounting gaskets and double check the carb body for a loose or missing plugs/fittings. Could be the mixture screw seat and needle mismatch, but not sure that would be a big enough leak to cause it to run that lean.

 

[hullofalottatrouble]

Re: problem diagnosis

hmm.. how about a damaged seat and needle mixmatch?

should note that i had a backfire through carb when tried to up throttle slightly..

i probably did have a slight vacuum leak before the carb needle problem.. i never did get the timing set dead on that time or get a chance to adjust the needles to optimize vacuum at idle.. had a leak in the therm housing so shut it down before could do too much..so that's something ill need to check out..

but the change in performance was so extreme..well in any event.. im going to have the carb checked out.. see if that solves it for me.. or at least start there and then move on to trying to determine where i might have any other vacuum leaks..

thanks for the help.. guidance.. and thoughts on this..

 

[hullofalottatrouble]

Re: problem diagnosis

well i checked all the plugs again.. and put them all back on again.. i think they were all perfectly fine.. and they are definitely fine now..

this time i couldnt even get the engine to start.. noticed that the choke was open a bit more than i would have expected.. like all the way.. i shut it but it would open right back up when engine was turning over? dont know that ive ever noticed that before?

the needles are from the same manufacturer # carb but it seems to me that the bent needle might be a little bit thicker at the tip.. its just eyeballing

i dont know.. very frustrating now..any thoughts?

 

[searay3]

Re: problem diagnosis

Tried the search for your other post, but no luck. Still have to learn how to use it right. Anyway, you installed a reman engine. Long block, short block or complete engine including manifolds (intake and exhaust). A cracked intake or leaking gasket on the intake manifold will give you the same symptoms. Choke has to be closed at startup and open as it warms. If the engine is cold, pump the handle once about 1/2 throttle. That should set the choke. It should be fully closed with some spring tension holding it that way. Once it fires the choke should open to about 1/8th inch (.125 drill bit). As the engine warms it will open fully. Are you sure there is no open port on the back of the carb maybe? Still think it's a big vacuum leak somewhere...

 

[hullofalottatrouble]

Re: problem diagnosis

installed a reman long block..i had 15 vacuum first time it ran which i admit is a little low.. but based on what ive tracked down could be a small vac leak or timing is off..

the first time i started it.. i started and ran it for a few minutes.. stopped it.. started it again.. it would start up fine.. run every time.. needed to idle a little high but sounded very strong.. started and stopped maybe 4-5 times..

it wasnt until like 2 days later that i got the new carb and therm housing gasket to try it again.. and now i am where i am.. cant even get it started..

any thoughts this is a malfunctioning ignitor II or something?

i would have expected a big vacuum leak to show up way lower on the gauge? like 5-10 vrs 15 dead solid?

thanks for the conitnued feedback.. i am getting very very frustrated.. about had it.. :-(

 

[hullofalottatrouble]

Re: problem diagnosis

ok.. well if i pump the throttle like 8-9 times.. and hold it maybe 1/4 it will start.. and half way sound like it wants to run.. hits that 15 vac reading again.. then it will sputter and die..

i have repeated that about 3 times now... pretty much the same thing every time.. it doesnt always start when i do that but had 3 times.. and it pretty much just backfires out the carb or exhaust.. and doesnt do anything..

i give up.. thanks for all the help..

 

[searay3]

Re: problem diagnosis

[colour=green]the first time i started it.. i started and ran it for a few minutes.. stopped it.. started it again.. it would start up fine.. run every time.. needed to idle a little high but sounded very strong.. started and stopped maybe 4-5 times..

it wasnt until like 2 days later that i got the new carb and therm housing gasket to try it again.. and now i am where i am.. cant even get it started.. [/colour]

Sounds like this started after you installed the new carb gasket. Your going to have to start there. Something has to be different from the original carb mounting gasket
.
[colour=green]ok.. well if i pump the throttle like 8-9 times.. and hold it maybe 1/4 it will start.. and half way sound like it wants to run.. hits that 15 vac reading again.. then it will sputter and die.. [/colour]

Running out of fuel, are you sure the choke is working properly? Did you get the distributor tightened down after the 1st start as you stated you wanted to earlier?
If not, it could turn as you are cranking the engine over.

Do you have a good manual for your engine? Should have a no start troubleshooting guide.

 

[hullofalottatrouble]

Re: problem diagnosis

well what do ya know if you keep pounding me in the head i will eventually listen.. it appears it was at least a timing issue.. and still may have more problems.. but i went back to basics on this thing and it starts.. every time.. and runs..

appears that my throttle cable is binding a bit.. i loosen the idle screw and the cable doesnt come with it.. so the idle doesnt actually change.. until i force the cable..

the vacuum guage is around 17 now but a little twitchy..

i am guessing i cant set the timing dead on correct unless i have the thing at the correct idle? i cant even see my timing mark when i try now.. its bright out and all but still.. it seems to on the other side of the balancer when its running now..

it is still definitely not running as solid as it was the first time.. and i was able to see my timing mark that first time i ran it.. still missing something here?

i do have the merc manual for the engine..

 

[searay3]

Re: problem diagnosis

Set the timing by the manual and adjust the mixture screws and idle (cable and carb) and it should be good to go.......glad it's working out for ya...

 

[hullofalottatrouble]

Re: problem diagnosis

now i have no spark at my coil.. lol.. imagine ive been turning the engine over too much without getting much/any recharge on my start battery?

i have the dist lined up now for #1 on compression stroke at 8 btdc its pretty much 6 oclock on the dist.. i have all the dist plugs labeled with the cylinders in the correct firing order..

but now since i dont have any spark at the coil.. im at a stand still... swapped out coils.. its the same for both.. guessing weak battery at this point..

glad to see ive made some progress.. i am proof positive that hard headeness will get you nowhere.. everybody saying plug wires and timing.. just takes me a while i guess..

thanks for all the help.. hope to get this thing purring before end of this weekend.. after i get battery charged..

or is my thinking on that off too? i cranked that thing over like a hundred times with no charge it seems..

thanks

 

[hullofalottatrouble]

Re: problem diagnosis

question for ya..

my rotor seems to have a heck of a lot of play in it.. is that normal? i have no idea here so thought i would ask.. i imagine when the cap gets tightened down and the thing is turning it gets set in ok. but it still has a lot of wiggle back and forth in it..

 

[tommays]

Re: problem diagnosis

You don’t say what OLD the parts you reused are BUT on the few older motors I have changed many things like the distributor have seen better days

The weight pivots are rusted and worn so it doesn’t give a proper advance curve anymore JUST one of many possibilities when reusing old parts

Manifolds and risers are past the point of reusing ECT


Tommays

 

[hullofalottatrouble]

Re: problem diagnosis

new parts would be

reman long block
starter
reman carb
pertronix ignitor II
flame thrower coil
plugs
plug wires
dist cap

everything else is swapped over from the old block

noticed that it appears that one of the plugs wasn't firing much if at all.. rest of plugs had that tan look.. this plug looked like it was brand new? replaced the plug and will check all the plugs again..

 

[KaGee]

Re: problem diagnosis

noticed that it appears that one of the plugs wasn't firing much if at all.. rest of plugs had that tan look.. this plug looked like it was brand new? replaced the plug and will check all the plugs again..

That could be a possible sign of water getting in.

 

[hullofalottatrouble]

Re: problem diagnosis

plug wasnt wet.. no sign of water in oil.. and also crank cyl and no sign of water in cyl...

going to check plugs again.. this time pay attention to which cylinder came out of and investigate futher..