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    350 Mag Mpi hard to start when warm or hot

    Inlet & exhaust lifters stuck up against retaining clip. Soaked them overnight in a new WD40 super penetrating fluid & they fell apart. Cleaned & reassembled them & they are working fine & motor now starts when hot. One tappet was noisy but once engine was warm & an increase in revs it soon...
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    350 Mag Mpi hard to start when warm or hot

    Just to clarify the lifter is all the way down it is the plunger which is not retracting at all it is fully extended against the retaining clip
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    350 Mag Mpi hard to start when warm or hot

    I have definitely done it that way. For some reason the lifters on this cylinder suddenly developed this fault where the valves no longer closed properly - there was no human intervention that did this. There must be a fault with lifter for it to do that surely?
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    350 Mag Mpi hard to start when warm or hot

    I don't think you guys realise I have a problem with a fully extended plunger. I can see the lifters & if it wasn't for the lifter guide I would be able to get them out without removing manifold as when I get a magnet on them the lifter body lifts up until it hits the lifter guide. If you look...
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    350 Mag Mpi hard to start when warm or hot

    If valve is closed with zero lash & before the 1 turn past zero lash there is no up/down movement is that a problem?
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    350 Mag Mpi hard to start when warm or hot

    Thanks that might be issue too. No tdc marker on front of engine & engine is so tight a fit I can't see down there anyway. Have been judging tdc by valve positions maybe I need to review that. Am I right in thinking that when valve is closed some oil drains out of lifter? On the no 1 valves for...
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    350 Mag Mpi hard to start when warm or hot

    Ok thanks Alldodge I will try that again in morning & report back. I had the boat surveyed when I bought it & the compressions were all reported to be in 157 - 170 range.
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    350 Mag Mpi hard to start when warm or hot

    Thanks for reply. I screw rocker nut down until no lash or play. But when I tighten 360 degrees as per manual it opens the valve. Is that correct?
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    350 Mag Mpi hard to start when warm or hot

    Good news but I am a bit confused here might need some help. It was exhaust valve that was stuck open. Exhaust valve on no 7 was not stuck open it was because rocker arm was tight. As soon as I loosened rocker arm off it closed. Did compression test still zero. Noticed no 7 Inlet was slightly...
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    350 Mag Mpi hard to start when warm or hot

    Put my leak down tester on today & I have air coming out of the intake plenum so looks like a fault with the Inlet valve. With my camera I can see valve opening as I rotate engine but it doesn't seem to be seating properly. I can actually see it standing proud at tdc. Can't think what would be...
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    350 Mag Mpi hard to start when warm or hot

    Camera down plug hole bit tricky to decipher at 1st but in the bottom 1/3 of pic is the original cross hatching of the cylinder & valve open on right. In middle of pic you can see outer circumference of piston - no visible damage. The top half of pic I believe is a piston surface that has been...
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    350 Mag Mpi hard to start when warm or hot

    Update 5: diagnostic revealed misfire on cylinder 8. Plug burnt electrode & black. Replaced spark plug now starts when hot. Tech said still a misfire which I couldn't hear until he pointed it out. Compression test revealed only 5 psi on that cylinder so I either have hole in piston, damaged...
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    350 Mag Mpi hard to start when warm or hot

    Thanks just found it in manual will try that before diagnostic test.
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    350 Mag Mpi hard to start when warm or hot

    Interesting I hadn't considered coil. I hope it is something as simple as that. Thanks for reply
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    350 Mag Mpi hard to start when warm or hot

    Update 4: Boat booked in for a diagnostic test next Tuesday. I have checked grounds to other sensors all ok. However I did attach a vacuum gauge to the Inlet manifold & it is reading 12 Hg when it should be around 17-18 Hg so the map sensor is reading correctly. I will get them to compression...
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    350 Mag Mpi hard to start when warm or hot

    Thanks for reply. I had ground connection on my multimeter attached to the battery when i checked sensor 5v when it should probably have been on engine ground. I will recheck tomorrow.
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    350 Mag Mpi hard to start when warm or hot

    Thanks for reply. I will double check ect values in morning (night time here in Oz). As I increased the revs it seemed to progress to around 1.6v & stay there but I will check again.
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    350 Mag Mpi hard to start when warm or hot

    Thanks for reply. I did consider injectors at 1st but as the fuel rail was holding pressure I discounted that. Might rethink that now.
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    350 Mag Mpi hard to start when warm or hot

    Update 3: I can't get a diagnostic done for a couple of weeks. In the meantime I checked the map sensor signal voltage at idle & it was 2.6v when the ecm 555 manual specifies 1 - 2v. I put a new non oem map sensor on & that also reads 2.6v & when I open throttle it drops to 1.6v which is strange...
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    350 Mag Mpi hard to start when warm or hot

    Update 2: I tested the injector wiring with a noid tester light & that is OK so I am getting fuel. I tested for a spark with a timing light & that is good as I have a spark. What I have discovered is if I take the PCV valve hose off engine starts when warm/hot. This indicates I am not getting...
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