QuestionQUESTION: I have a B&S engine 3402437 0770 01 on a Bolens mower. It will not run unless the choke is completely closed and then only at about 1/3 throttle. It will idle with the choke open and will run full throttle if gas is misted into the carb throat. I cleaned the fuel tank, replaced the shut off, replaced the fuel lines and in-line filter,rebuilt the fuel pump,rebuilt the carb and thourghly cleaned the passage ways and replaced the fuel pump pulse line. When I started the engine with the air filter off it ran the same as before(needed full choke). I replaced the air filter and it started up and ran fine. Icut my lawn(approx. 2 acres) twice. Two days later when I started it, it again wouldn't run without full choke. I redid the pump and carb and everything looked ok but it still would not run without full choke. Compression is 100# in pulse line side and 110# in the left bank.Crankcase breather has a slight oil residue on it but no oil in the pulse line.The engine does not burn excessive oil-about 4 ozs. 6 or seven hours of wide open throttle cutting grass. Where do I go from here? Thanks for your help.
ANSWER: Hello Dave:
>>I Think this is a 302437-0770-01 Model Engine.
>>Always Remove the Spark Plug Wire/s from the Spark Plug/s before Working on Any Small Engine unless the Plug/s must be Connected to the Coil/s for Diagnostic Reasons.
>>If you are Sure you have the Carburetor Clean and it is Not the cause of this Problem, then
>>Does the Point Set have the Correct Clearance (.015in - .020in)?
>>If the Point Set Clearance is Not Correct, then you will have this Problem.
>>Check the Valve Clearances.
>>The Following is a Basic Instruction File for Setting the Valve Clearances on Non OHV Engines. If you Provided me with the Correct Make and Model of the Engine then the Specifications are Included. If Not I May be Able to Provide the Specifications if you Supply me the Make and Model Numbers.
>>The Most Common Clearances are Listed for this Engine in the Following File. Thanks. Any Input is Appreciated.
>>On this Model Engine I Usually Suggest Re-seating the Valves if the Valve Clearance Requires Adjusting.
>>**Remove the Carburetor and the Crankcase Breather/Vent and the Valve (Stem) Cover so you have Access to the Valve Stems, Springs and Keepers.
>>Set 1 Cylinder (on Twin Cylinder Engines) to TDC on the Compression Stroke. Using a Blade Style Feeler Gauge, Check the Clearances. The Intake should be; .007in - .009in and Exhaust .017in - .019in. If the Feeler Gauge will Not Slide Between the Valve Tip and the Tappet, then you Must Reset the Clearances.
>>**You Will Require a Small Engine Valve Spring Compressor to Remove the Springs and Keepers from the Valve Stems.** Some Engines Use a Valve Keeper that is like Automotive Keepers (2 Cone Shaped Keepers that Set in the Valve Retainer/Rotocoil Assembly)and the Other Style is a Slotted Retainer that is Moved (once the Valve Spring is Compressed) to the Larger Opening in the Retainer and the Retainer Slips Over the Valve Stem Tip for the Valve to be Removed.
>>Remove the Heads.
>>Set 1 Cylinder so the Piston is at TDC on the Compression Stroke And Check the Clearances Between the Valve Stem Tip and the Tappet. The Clearances are as Follows: Intake Valve Clearance is .007in - .009in and the Exhaust is .017in - .019in.
>>You have to Lightly Grind the Valve Stem Tip and Place the Valve Back Into the Engine (you can Hold the Valve Seated by Hand) and Check the Clearance Until you Reach the Required Clearances.
>>**++** For this Engine Model I Suggest you Reseat the Valves while you are Setting the Correct Valve Clearance. For this you will Need a Small Valve Seat Suction Tool. This can Usually be Purchased for $10.00us and has a Suction Cup that Hold the Valve Head so you can Turn the Valve Back and Forth and Dress up the Valve Seat. Valve Grinding Compound is Approximately $5.00us a Tube and a Tube Last the Shop About a Year. It Doesn't Take a Lot to Re-seat 1 Engine.**++**
>> Once the Valve Clearances are Reached and the Valve Seat is Nice and Dull; Re-Install the Valves on that Cylinder and Turn the Other Cylinder to TDC on the Compression Stroke and Set that Cylinders Valve Clearances.
>>Once that Cylinder is Set, then Assemble the Engine.**
>>If you Hit a Snag or this Does Not Correct the Problem, I Hope to be Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Be Safe and Happy. Thanks.
Good Luck
Respectfully
John
PS: I am Allowed to Answer 5 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 8pm EST (US). My New Day Starts then. Comments and Ratings are Greatly Appreciated. Thanks.
Respectfully
John
---------- FOLLOW-UP ----------
QUESTION: Hi John. I'm sorry about the mix up on the engine number. The correct number is 402437-0070-01. The mower is a Bolens model #1668 or 1600H. I had been starting it with half a tank of gas which put the gas level below the fuel pump inlet. I filled the tank today to bring the level above the inlet and it would run about twice as fast with full choke. I don't know if this means anything or not. The engine I have has an electronic ignition and pulse fuel pump. I have checked the pump three times and never found anything wrong. Thanks for your help. Dave
AnswerHello Again Dave:
>>Thanks for Clearing up the Model Numbers for me.
>>Check the Fuel Shut Off Solenoid.
>>The Following is a Basic Instruction File I made for Checking the Carburetor Solenoid. Any Input is Appreciated.
>>**Check for Current/Voltage (10.5 VDC Minimum) to the Carburetor Shut Off Solenoid. If the Carburetor Shut Off Solenoid has Current, then On Some Solenoids you can Remove the Needle and Replace the Solenoid to Test them.
>>****PLEASE DO NOT OPERATE THE MOWER WITH THE SOLENOID BYPASSED IN THIS MANNER. THIS IS "ONLY" FOR TESTING.****
>>For Others, Remove the Carburetor Solenoid and Go to the Hardware Store. Purchase a Bolt of the Same Diameter and Threads. It Needs to be 1/2" to 3/4" Long for the Horizontal Mount Solenoids and 1/4" to 1/2" Long for the Vertical Mount Solenoids. Put this Bolt in Place of the Solenoid. If this Corrects the Engine Problem, then Replace the Solenoid.
>>***NOTE: THIS IS FOR CHECKING THE SOLENOID ONLY I NEVER SUGGEST YOU OPERATE THE ENGINE WITH THE SOLENOID OUT OF THE CARBURETOR EXCEPT FOR TESTING PURPOSES***
>>Sometimes the Plunger is Moving, Just Not Far Enough to Allow the Gas to Enter the Jet Properly.** **Use 440 Wet Dry Sand Paper and Engine Oil to Clean the Pin. Wet the Sand Paper with Oil Until it is Flexible and then Lightly Polish the Pin. There is Some Slop/Free Play in the Solenoid Pin. Usually the Electromagnet is Simply Not Pulling the Pin as it Should or there is a Small Bur on the Pin. Use 440 Wet Dry Sand Paper and Engine Oil to Clean the Pin. Wet the Sand Paper with Oil Until it is Flexible and then Lightly Polish the Pin. Clean and Lightly Oil the Pin before Inserting it Back into the Solenoid. Just a Film of Oil is All it Takes.**
>>Have you Replaced the Spring Style Hose Clamps with Screw Style Hose Clamps on the Fuel System?
>>If this Does Not Correct the Problem, then
>>Check the Valve Clearances. The Instructions I Sent Earlier are the Correct Instructions for Checking and Setting the Valves on this Engine,
>>You can View a Breakdown/IPL of this Engine at this Site Addy, http://www.outdoordistributors.com/ and Select the B. Then Select Briggs and Stratton. Then Select Don't have Part Numbers. Then Select the File #40 . Then Select the Folder #402400. **Note: you can Download and Save the Breakdown for your Engine by Selecting the 2nd Icon from the Left at the Top of the PDF page.**
>>As Always, If you Hit a Snag or this Does Not Correct the Problem, I Hope to be Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Be Safe and Happy. Thanks.
Good Luck
Respectfully
John
PS: I am Allowed to Answer 5 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 8pm EST (US). My New Day Starts then. Comments and Ratings are Greatly Appreciated. Thanks.
Respectfully
John
