Description

Generac 1.6 Service Manual

If you’re pulling a cylinder head off a Generac 1.6L Chery gas engine without the factory service manual, you’re betting your time and parts on luck. I’ve seen snapped crankshafts and bent valves because someone guessed the torque sequence or skipped the timing belt adjustment. This 76-page service manual from Generac gives you the exact OEM procedure – not a third-party reprint that leaves out critical specs. Page 1 lists the manual part number OG3865 – that’s your proof it’s the real deal.

Generac 1.6 Service Manual: Engine Disassembly and Assembly

You start with positioning No.1 cylinder at top dead center (compression) – section [1] in the manual. Then you work through the timing gear covers, crankshaft pulley, valve cover, and timing belt. Each step has a required tool list. The manual doesn’t assume you know which way to turn the tensioner. Section [5] walks you through timing belt removal, installation, and adjustment with the proper tension specs. Skip that and you’ll have a valve hitting a piston inside 50 hours.

Every time I open this manual, I check the valve clearance specs for the cylinder head (section [8]). The factory gives you the cold and hot clearance values. Aftermarket manuals often leave that out. Page 2 of the foreword warns: “Proper service and repair is important to the safe, economical and reliable operation.” That’s not fluff – that’s a liability statement. Use the wrong clearance and you’ll burn a valve seat.

Timing Belt and Tensioner: Factory Adjustment Procedure

Section [6] covers the tension pulley, crankshaft gear, and camshaft gear. You’ll need a torque wrench that reads in inch-pounds for the tensioner bolt – the manual gives the value. I’ve seen guys use a 3/8″ ratchet and guess; that’s how belts slip. The procedure also includes a visual check of the crankshaft gear teeth for wear. Don’t ignore that. A worn gear will eat a new belt in 100 hours.

7 Systems Covered in the Oiling and Cooling Chapters

Sections [13] and [14] detail the engine oiling system and cooling system. The oiling section covers the oil pump, pressure relief valve, and the passage cleaning procedure. The cooling section lists the thermostat opening temperature and the coolant capacity in quarts. If you’re flushing the system, the manual tells you the bleed sequence. Overlook that and you’ll get an air lock that overheats the cylinder head.

Valve Clearance and Cylinder Head Torque: What’s Listed?

Section [8] – valve mechanism and cylinder head removal, check, and installation – gives you the bolt torque sequence in three stages. You need to torque the head bolts in the correct order, then do an angle turn. The manual specifies the angle in degrees. I’ve seen guys skip the angle and wonder why the head gasket leaks. The valve adjustment procedure is also here: intake and exhaust clearance values. Write them on the bench before you start.

Carburetor Engine Faults – Troubleshooting Table

The last section of the manual is a table of carburetor engine faults, causes, and corrections. It lists symptoms like hard starting, misfire, and low power. For each symptom, it gives the likely cause (dirty carburetor, incorrect float level, clogged jet) and the corrective action. This is the part you’ll flip to when the engine won’t start after a rebuild. It’s saved me hours of diagnostic time.

Does This Manual Cover the Crankshaft and Bearings?

Section [11] covers removal and installation of the crankshaft, crankshaft thrust washer, bearing halves, and main bearing cap. The manual specifies the bearing clearance range and the Plastigage procedure. If you’re replacing main bearings, you need this data. Aftermarket manuals often give a generic range – this one gives the exact factory spec. You also get the thrust washer thickness and placement. Get that wrong and the crankshaft walks.

For related engine manuals, check out the Generac 13.3 LITER Service Manual – OEM Factory Specs for larger diesel engines, the Generac 13.3 1997 Parts Catalog – OEM Diesel Parts Manual for parts identification, and the White Outdoor LT-5 700 Series 2005 Service Manual – OEM Factory Specs for small engine service. If you’re working on a manual transmission, see also Manual Transmission and Manual Transmission for general transmission service principles.

Does this manual include torque specifications for the cylinder head bolts?

Yes, section [8] lists the torque sequence and angle values for the cylinder head bolts. The values are in foot-pounds and degrees.

Can I use this manual for a 1.6L engine that is not a Chery?

This manual is specifically for the Generac 1.6L Chery gas engine. Using it on other engines will give wrong specs – especially the timing belt routing and valve clearance.

What is the page count and format?

76 pages. Format is a digital PDF format. You can print the pages you need for the job.

Does the manual cover the carburetor adjustment?

It covers carburetor engine faults, causes, and corrections in a troubleshooting table. It does not provide a step-by-step carburetor rebuild procedure, but it does list common issues like float level and jet clogging.

Access the Factory Manual and put it on your tablet or print the sections you need. Having the OEM procedure on the bench means you don’t have to guess the crankshaft thrust washer position or the timing belt tension. That’s the difference between a 50-hour rebuild and a 500-hour engine.