99 DF50 oil light and unresponsive tach needle

[Elliot Griffin]

I replaced shortblock and head on 1999 df50 and ran it for first time tonight. All sensors and wiring were reused. I didn't disconnect the harness from tach during rebuild. Upon turning key to on, the rev light on tach flashes and buzzer chimes as normal. I let it warm up on earmuffs and idle a while before putting in drive. I noticed tach needle never moved. After I changed from drive to neutral I got oil light. I shut it off and checked oil level, no issue. I started it again, and again the oil light came right after going from drive to neutral but that time the engine stalled and died. I verified continuity from oil pressure switch to ECM harness connector. I have SDS but haven't played with it yet. I never observed these issues before the rebuild. Suggestions?

[redlowrey]

If you have just put this engine back together, you should connect up an oil pressure gauge and make sure you have good pressure. I never start an engine that I have just rebuilt without a gauge connected up. Give the rev counter gauge a tap, the needle might be stuck.

[Elliot Griffin]

Thanks!
Should I follow the manual 2-26 and connect gauge below oil filter, see attached? Before I start it again, is there anything I can do to check pump is primed? I primed pump before mounting oil pump housing on block, but I think that little bit of oil drained out when I righted the power unit to put it on engine holder. I found a MAC oil gauge which looks like it will work, but I've never used it before.

[Elliot Griffin]

I did a oil pressure test just cranking not firing with two different gauges: the old MAC gauge read 7 psi whether it was on service port or pressure switch port. The new HFT gauge didn't move at either location. Both gauges seem to measure pressure from my home air compressor okay. Service manual says 43-54 psi at 4K RPM. I don't know what expected pressure is for starter motor speed. Should I fire it up with old MAC gauge on service port?

I did a cold compression test with a new HFT gauge and measured only 120 psi. Manual says warm should be 185-228 psi. I can check it warm, but I'm generally concerned. Of course, it ran fine on hose (no load) which is a sign of progress. And a Suzuki shop said my old shortblock and head, which wouldn't start at all, had 217/171/120 psi. I did a leak down check before I installed the cams, which gave normal 10-20% results.

[redlowrey]

At this stage concentrate on the oil pressure, if you can remove the filter and lay the engine on it's side, pour some oil down the suction side, stand it back up, fill the filter and put it on, start the engine and let it idle, You should have at least 20 psi if it is pumping. If you have some pressure the pump is primed but you are loosing it some where, if you don't have any I think you may have a problem. Don't leave it running for more than ten seconds if you have no pressure.

[Elliot Griffin]

Thanks very much for all the guidance, I need it.
Motor is on boat, and boat is on trailer. So laying it down on side would likely involve a tree branch and a come along. Any alternatives I could try, maybe take off filter, squirt oil into the suction hole, replace filter with oil in it (horizontal filter, some oil will escape), refill as necessary through valve cover port? Or hand turning flywheel and using mityvac to pull oil toward pressure switch port? I'm just throwing out ideas. Is the service port on the suction side, between pump and filter? See attached

[Elliot Griffin]

DF50 won't idle without warm up lever on

Tach is working. Fixing some loose connections restored it.
Oil pressure is 30 psi at 1200 rpm with warm up lever on. I assume this is normal.
I couldn't start it without warm up lever, ambient air is 65F/19C. That seems abnormal, and my focus issue now.
I let it run for a while on warm up lever. It was peeing strong warm water. Hottest thing I could measure on surface of block with IR was 120F.
When I turned off warm up lever, rpm decreased to ~800, oil pressure decreased to 15psi, oil light came on and engine died. I checked oil pressure switch with air gauge and compressor and it turns on at specified pressure ~15 psi. Manual says 10-19psi.

Manual says normal idle speed range is 800-900 rpm.

Any suggestions?