Df40 and error code 3-2

[Allan Strachan]

Pull the cam cover off and check the clearance on all the buckets you will probably find a tight valve on the cyl with low comp.

hi, yes tried that and plenty clearance.

Stripped down the block and head. Pistons, liners all good. the ring gaps are even within new tolorances and showing negligable wear.

two bad inlet valves and one of the exh valves on its way on the affected cylinder. Looks like i've caught it just in time, the valve seats look pretty good. the valves on the other two cylinder also look like they need a good clean up and lapping in again.

can't wait for cam clearance re-shimming job (yeh right)

Thanks for all the help so far.

Al.

[Allan Strachan]

the saga continues!

I've rebuilt the engine. Stripped and took the block and pistons to a local boat builder.Bore wear was non existant, ring gaps were all within the 'as new' spec. Local outboard repairer also looked at the block and advised that there was no point changing the rings since they were 'as new'. Only thing done was a mild deglazing of the bores. all bearings were spotless.

onto the head. pooling turpentine into cyl 3 valves showed leaking past both inlet valves and one exhaust, so they all came out. I ended up replacing 3x valves on cylinder 3 and reground every valve on the head. The head was fully decoked and was spottless.

Valve buckets were all reshimmed and all confirmed as being within manufacturers tolerances.

Now today i got the motor together and fired it up. Guess what? yes same fault!

redone the compression test and now get 165 across all 3 cylinders (give or take 1-2psi)

Manifold vacuum isn't much different. it still flicks between 10-12 hg erattically on idle, and a throttle blip will produce 17hg at best.

I'm thinking it could be valve timing. I definately put it back the way it came off. What it did notice, was that the the mark on the engine block for lining up the sprockets, doesnt line up with the coloured marks on the timing chain. I went (as it was originally) with the marks on the chain, and as close to the block marks as possible. this left the crank mark sitting closer to 5 oclock rather than the 6oclock mark on the block, however, as i said, the cam sprockets lined up with the block and all the coloured chain links were exactly aligned with the crank and cam. Setting it to the block and having the crank mark one tooth away from the coloured link i guess would be a possibility?

The manual states 180 to over 200 as a healthy compression, so i'm guessing that low compression and low vacuum are possibly being caused by the cam timing?

Anybody with any other ideas before i rip the head off again and try the cam timing the other way? The engine is definately without a doubt in tip top condition.

ps, what also doesnt help is that the cam marks on the block are more of a raised bump than a definate line. This doesnt help!

MY mate who owns the boat also confirmed that its always been like this, and there was plenty evidence of a previous engine rebuild (excessive instant gasket everywhere, in fact, the sump was full of it).

cheers, Allan

[tugboat]

Hi Allan I have a similar fault on my DF50 as on forum few days ago, I have had my engine from new and my compression is bellow 180 but all are equal, my fault only occurs when l have been running fast and go to tick over, it ticks over for a while about 30 seconds slows down stops and alarm goes, if I stop it or open the throttle it's no problem but seems funny your alarm for map pipe goes when first switching on, all it's doing is reading atmospheric pressure, you seem to know more about engines than I do but have you checked the wiring and plugs for corrosion there should be a drawing in manual.
Hope this helps T (it's grim here in Yorkshire as well)

[redlowrey]

When the crank is at six oclock the two horizontal marks on the cam gears should be level with the top of the head, if it is the same as a df140. **** plate on chain lined up with dot on bottom of driven gear, blue plates lined up with dots on camshaft gears, hope this helps.

[redlowrey]

That should have read **** plate

[catacom225]

Map

I had the same prob, before and after a rebuild. In short and after much testing I simply replaced the IAC valve , crossed it with a suzuki motor car, i think was a vitara which i got from a auto dismantler, reset air idle adjustment as per the manual, After many months of testing problem disapered

[tugboat]

That's certainly worth remembering, just got rid of a petrol injection vitara and put all the spares I had in it as well who would have thought.
T

[Allan Strachan]

right, i've just spent the whole day on this this thing. I wasnt going to be beaten by it!

took the powerhead off and got her laid down, timing cover off and started to play. Tried the chain either side of where it was set to originally and it didnt look right. the way it was looked to line up the best.

close to boxing it all up and pulling to a repair house i decided to drop a little oil down the bores and do a minor compression test with the engine on the bench. All spark plugs out and compression tester in cyl 1, i strapped the engine down to the bench and got the jump leads out. a couple of cranks in the original position and i got 160psi as i expected, changed timing one tooth the other way and got 140psi. changed it one tooth to the other side of the crank mark (chain lining up with everything, except the 6 oclock crank mark was at 7 oclock and HEY PRESTO 210psi.

just got the power head back on, fired it up and it is running like a dream. Its so quiet and smooth and picks up the RPM at a fearsome rate.

Thanks for all the help!!

One incredibly happy and relieved Al. I'm off to break open a well deserved beer!