Background & Reason for Overhaul: Engine Model: Yanmar 4TNV98-GGE (Power Generation Spec). Cylinder 1 Location: Flywheel end (Rear side). Initial Symptoms: The engine had no starter, with massive carbon buildup inside the intake manifold and around the injectors. Root Cause Found: Upon pulling the timing cover and idle gear, the camshaft and crankshaft marks were perfectly aligned, but the Fuel Injection Pump (FIP) gear was found 4 teeth retarded relative to the idle gear (causing incomplete combustion and heavy carbon setup). 2. Current Setup & Dial Gauge Issue: Gear Alignment: The idle gear was reinstalled with all timing marks aligned (Crank, Cam, and Pump) while the engine was at TDC Compression on Cylinder No. 4 . Dial Gauge Behavior (Plunger Lift Calibration): With the engine at TDC for Cylinder No. 1 and the dial gauge installed in the rear FIP inspection plug, rotating the flywheel counter-clockwise by 30^degree results in zero movement on the dial gauge needle . However, when rotating the crankshaft further forward by approximately 180^degree(half turn) , the dial gauge suddenly responds and measures a full stroke of 10 mm . A note about myself: Iam a final-year Agricultural Engineering student. Working on this Yanmar engine is a personal hands-on challenge for me to learn proper diesel overhaul procedures. Unfortunately, in Egypt, correct technical timing and precision alignment using dial gauges are rarely practiced in local workshops—most rely on guesswork, which leads to issues like this. I am determined to do this job the right, scientific way. Questions: Timing Phase Reference: On the Yanmar 4TNV98 (where Cylinder 1 is at the flywheel side), is it standard procedure for factory timing marks to align on Cylinder 4 Compression , requiring a single 360degree crankshaft turn to bring Cylinder 1 to its compression stroke for calibration? Dial Gauge Inactivity: Does the zero needle movement at TDC Cylinder 1 (and the 10mm lift occurring 180^ degree later) confirm that the pump plunger was simply on a non-active stroke/flat base circle because the engine was physically on Cylinder 4 compression? Step-by-step Verification: What is the recommended sequence to verify that the pump drive keyway, idle gear, and 2.5 mm plunger lift at BTDC injection angle are correctly set for Cylinder No. 1 without removing the timing cover again?