YSB8 Wonbt start Compression leak down handstart

"Number one question is How lo

"Number one question is How long should the compression hold when held at compression with hand start crank?

The following is for a little back ground, hopefully someone can add some comments.

As I am looking at taking the head off which means cutting a hole in the engine/battery box to get head off.
I can hear air leaking more clearly with exhaust off.
Did not time leak down to engine turnover with hand crank but guess at 6-8 seconds will time next time.
Difficult to start 4 weeks ago but ran fine when
started.
Engine rebuit 3-400 hrs back, just bought boat.

Fixed fuel air leaks.
Injector removed and it sprays at least 12"
Removed exhaust - elbow not plugged

Did find exhaust valve at .013" gap.
Intake = 2mm = .008"


Oh yea when engine ran quite a few days back , no black smoke, no blue smoke , no residue on water, some white smoke. Never missed a beat at 850, 950 , 1200 rpm in gear.

The last time it started it went from 1000rpm
down to approx. 600rpm slowly never to start again.

Really need some experience to guide me

Thanks in advance
Gord
Sointula
No service / dealer for 150 miles"

"G'day Gord,
Ca

"G'day Gord,
Can't say i have ever timed the leak down time on a ysb at a guess may be around 15 secs should be expected,injector spray should be a mist fan pattern if you turn the injector out and turn motor over put a match in pattern you should get a clean ignition flame.
Take air inlet pipe off ,squirt obout half a T spoon of oil into cyl if motor fires easier you have a compression problem, also check throttle linkages at fuel pump are free moving. Cheers, Shakey.
PS. Are valve rotater caps in place?"

"Thanks for the info Doug

I

"Thanks for the info Doug

I took the injector nozzle apart and scrubbed all parts with rust remover and paper towell
The needle valve was not sliding in/out at all
, it was very very sticky, it now falls out when
held vertical. Haven't installed yet.
Removed exhaust, not plugged, cleaned and installing now.

Did not try lighted match and injector spray, a little nervous doing this , not sure about diesel fuel. I have visions of burning my little boat to the water line.

Both valve mechanical parts seem to be identical. No missing parts are obvious.
both valves move in /out the same.
I did adjust the intake as it was around .012"
instead of .008". I have intake at .008" goes .009" no go.

Drew out a 15 degree spray on paper and placed my injector at the center point and believe the
spray I say when testing with crank handle was
a fuel oil stream not a spray. hopefully
freeing up the needle valve will make a difference.

Hope to avoid removing head this year.

Will have to use a magnifying glass for a better look at rotator caps plus a bright light.

Thanks
gord"

"G'day Gorg,I reckon the s

"G'day Gorg,I reckon the seized pintle will be the problem, the way you have gone about fixing it- you must have done your time at one of our local shops. LOL! I hope it makes the right noises for you.Cheers, Shakey."

"Hi Shakey

Installed the In

"Hi Shakey

Installed the Inj Assy
No start/no put/no nothing.

Removed INJ Nozzle connected up externally and did handcrank no spray , had to air bleed 3 times.
Installed NOZZLE same thing no firing at all.

QUESTION: What is the best way of removing the
pre-combustion chamber?

Visual symptom: Sprayed some fluid around NOZZLE
assy. Some air bubbles appear on handcrank.

Question: What should be the Torque wrench setting for tightening these two nuts?

Audible sound (new) clunk sound when handcranked, decompression lever held on, can
feel a clunk/bang with hand when holding vavle cover & decompress lever. Did not notice this several days back. Does not appear to be a good sound.
Will have to take valve cover off again and observe rockers and valves.

Last nite removed High Pressure fuel pump and
removed outlet spring/ball assy. Removed regulator adjust assy. A lot of black fluid at first it looked like Lub Oil , have to assume
it was normal wear of O ring and brass regulator body(7).
The spindle was very sticky to rotate in/out.
Needle seemed good no noticeable wear under magnifier glass. The engine side plunger had some roughness on in/out movement, some shiny
spots also. After cleaning and rubbing with paper towell it is smoother in full travel.

Did not remove plunger barrell and screw.

Will install today.

It looks more and more like compression. It doesn't seem to have low compression as handcranking stops dead on compression.

Sure wish I had observed a perfect NOZZLE spray
to compare this one .

Unless something miraculous happens I will have to send the Nozzle & pump to the closet Yanmar
diesel shop 150 miles south of here. At least I will find out if I have a problem with either one.


Open to all suggestions and comments.
Doug your opinions are always welcome.

Gord
Sointula"

"Hello Gord,
Af

"Hello Gord,
After bleeding the system, and an out board motor squeeze bulb does help if you install one. This will push the fuel to the FI pump. Crack the nut on the injection pump, where the high pressure line from the injector fits in. They some times air lock. You need a new nozzel for the fuel injector by the sounds of it. Also the plunger and barrel may be worn, remove it and check where the plunger moves with in the barrel. If you see wear or discolouration on the metal change that also. Check the delivery valve & spring. These are simple pumps and no one has a basic test stand. A must is to get a service manual. If you can get a manual for the TS engine which is the Industrial version, it shows a better break down and how to adjust when you install the pump.
Hope this helps. All the best, Ron"

Thanks Ron

Your descriptio

Thanks Ron

Your description on the pump plunger/barrel is extremely usefull .
Yes I can see with good light that there is obvious
coloration difference on one side of plunger and a slight stickiness in one spot when rotating plunger and moving it in/out.

Nozzle needle is not so obvious but will replace it also.
Plus all gaskets .

Thanks