Engine start rotation binding.

[Spenceror]

Purchased AS-IS a not running 1982 Johnson 35HP outboard tiller model with rope start. Rope pull requires about 200 pound pull to just rotate the flywheel (only with both plugs in). With plugs out flywheel can be rotated completely by hand. Installed a new electric starter but it still will not rotate the flywheel to just before TDC on both pistons. <br />With plugs removed the flywheel flys with no resistance. Plugs are factory specified with short thread and about 1/4inch clearance between plug tips and both pistons.<br />Ignition wires disconnected with all troubleshooting. <br />Compression on both cylinders about 120 with light oil coating. Initially dry (storage) about 100.<br />Pulled head, found slight rust film on bores, cleaned with Scotchbrite and oiled.<br />Assembled with new starter, new fully charged truck battery, isolated starter wiring and connected directly with heavy short cables to 12.8volts and sheared the flywheel key. <br />Repaired damage, flywheel installed 105lbs torque on nut, tested without plugs, flywheel solid with no wobble. Flywheel teeth match starter teeth and mesh properly. <br />Checked exhaust with compressed air at spark plug ports and clear at bottom of both piston cycles <br />Flywheel still can not be turned past Ignition pulse prior to TDC with rope or starter which stalls out and pulls very high current. Voltage on 90Amp battery drops from 12.5 to about 9.5volts under load. I can’t check current over 20 Amps with my meter but the arc tells me the new ARCO starter is pulling at least 50 Amps. Installed compression meter on one cylinder with this test and read about 120. Remove both plugs and the flywheel and pistons spins smooth with very little resistance when turned by hand. <br />This problem is still there with the carbureator removed. <br /> I think the flywheel key will shear again is I continue at this point <br />Could the piston rings be rusted and bind under compression? Could the reed or leaf valves be defective?<br />Could the pistons be flexing or deforming under compression? <br />I’m lost at this point and may tear down the engine to inspect. Fishing season starts in April when the ice melts. Thank you all for the prompt help and suggestions.<br />

 

[Rex]

Re: Engine start rotation binding.

TIMING SET TO HIGH

 

[Backlash]

Re: Engine start rotation binding.

Hey Spence,<br />Did you do as Schematic suggested on your previous post? If not, you should. It'll give you your answer. <br />Backlash

 

[Spenceror]

Re: Engine start rotation binding.

I removed ignition wires from spark plugs and tested with same results. Also using Johnson recommended spark plugs QL77J4. The engine has never been able to start from the first day of purchase. How could engine timing be adjusted if there is no ignition? This problem is over my head. Thank you for the suggestions.

 

[petryshyn]

Re: Engine start rotation binding.

If I understand you correctly....<br /><br />>engine hard to crank with plugs in and wires off<br /><br />What happens if you crank with only one plug in at a time?<br /><br />Does each cylinder contribute the same amount of resistance?<br /><br />(use the pull start to determine this)

 

[MGuckin]

Re: Engine start rotation binding.

Timing......adjustments.<br />1) Throttle cam. Motor off. Aligns the timing marks.<br />2) Throttle control rod. Motor off. Synchronizes the throttle to the initial timing mark.<br />3) Needle valve. Motor running, sets idle speed.<br />4) Maximum spark advance. Check with light. Motor running but adjusted with motor off.<br />Clymer manual #B732 pages 116-120. Excellent pictures and directions. I obtained this manual after having the same problem.

 

[rwise]

Re: Engine start rotation binding.

Spenceror<br />Is/was this engine equipped with compression release? My engine is older and does have compression release. If it has this make certain that it works properly.<br /><br />Richard

 

[Spenceror]

Re: Engine start rotation binding.

Hi Schematic <br />Tested compression today, about 115 on each cylinder. Almost impossible to pull with cord.<br />Removed plug from cylinder one, Cord pull difficult but not impossible.<br />Installed plug one and tested with plug two removed, still difficult to pull.<br />Found pull to be identical on both cylinders. Guess about sixty pounds pull on each cylinder. <br />Noticed that during compression (just before TDC) and up to TDC there is resistance. At TDC there is no resistance and then it gets hard to pull after that until the piston almost reaches bottom (fuel intake?). This is when either cylinder one or cylinder two plug is removed. <br />When both plugs removed rotation is smooth, can not hear any scraping or noise from pistons or flywheel.<br />The flywheel is tight on crankshaft and is running level with no play or wobble.<br />Could rings on both pistons be the problem?<br />Could my 1982 35 Johnson pull start engine have a compression release? J35RLCND on tag. <br />It has not run (won't turn over) to adjust timing since I bought it privately.<br />Thanks for the suggestions.<br />Spenceror<br />

 

[G DANE]

Re: Engine start rotation binding.

I would try to remove carbureator and reed plate to see if anything is blocking your intake. Are u sure flywheel is engaged correctly to key ?<br /><br />Rope starter disc is eliptic to ease pull. If flywheel is 1/4 turn wrong, it will be very difficult to pull - around 4 times as hard !<br /><br />On the other hand, you had problems with the electric start too, but turning flywheel 1/4 turn will give you an ignition timing far too advanced, which will cause the electric starter to work overtime !!<br /><br />Schematic - do you think this can be possible ?

 

[G DANE]

Re: Engine start rotation binding.

Do a test spenceror<br /><br />Try to make the electric starter cranck the motor with both plugs in, but both plug wires off. You can put two old plugs in wires, grounded to protect powerpack.

 

[petryshyn]

Re: Engine start rotation binding.

>Is it possible that we have a bad starter?<br /><br />>Have you ever pull-started a motor of this size before?<br /><br />>Is it possible that this is normal for this engine and you haven't had others to compare to?<br /><br />>Don't be offended, we have to assume nothing...<br /><br />G Dane:<br /><br />Its apparently hard to rotate, even with plug wires off. That rules out timing and flywheel position...

 

[G DANE]

Re: Engine start rotation binding.

Spenceror<br /><br />Once again: When you tried to cranck with spark wires of, did you use the starter or rope pull ?

 

[Spenceror]

Re: Engine start rotation binding.

Hi Schematic<br />I’ve worked in field service for 35 years on medical electronics and xray equipment, prior to that US Army automotive vehicles back in the early 1950s, mainly as an instructor in automotive electrical system. The closest I ever worked on marine engines was on Army amphibious DUKs. I have learned the hard way that you can never assume anything and never claim to know all about any one subject. This engine has me going in circles. My gut feeling is that the problem is internal and at this point can only be diagnosed by disassembly. You and all the other fine people on this BBS have provided me with accurate and very professional information. It has been an education that I will use to fix this engine.<br />In answer to your suggestions: It is possible that this starter is defective, but why did the flywheel key shear and it pull so much current? It could also be internally shorting but with the plugs out it pulls almost no current. A new ARCO starter has been installed. 12Volts applied directly to starter with no other wiring attached. The current seems excessive at least over the 20Amp meter capacity. I plan on fabricating a shunt to get an accurate measurement and then call ARCO for specs. The crankshaft keyway matches the flywheel keyway. A few years back I had been out fishing with this same engine and yes, it was hard to pull then, but it still was possible to pull.<br />I’m ready to disassemble the reed plate and exhaust to see if there are any blocking obstructions <br />Again thanks for all the help<br />Spenceror<br />

 

[Spenceror]

Re: Engine start rotation binding.

Hi G Dane,<br />Yes I have tried to rotate this flywheel with both electric starter, which binds just before TDC and also with the rope which binds at the same place. Exactly the same results with ignition wires on or off. <br />Again, with spark plugs removed the flywheel can be moved easily with no resistance.<br />Thanks for the input,<br />Spenceror

 

[Hooty]

Re: Engine start rotation binding.

Senor Spenceror,<br />I've been watching this post and don't have anything to offer that hasn't been but the "binding" does sound like it's mechanical. How about, when you figger out the problum, drop us-all here on the board a post and tell us wtf. I would appreciate it and I think everyone else would.<br />G'luck & c/6,<br /><br />hooty

 

[petryshyn]

Re: Engine start rotation binding.

Spenceror<br /><br />Not sure on that model, but is it possible to put the reed block in backwards, or install them on the wrong side of the plate?<br /><br />just a thought.....leave no rock unturned....

 

[G DANE]

Re: Engine start rotation binding.

Spenceror<br /><br />Schematic can be right - when you look through the carbureator, reed blades must be on the opposite site of reed block, the motor side. Block cannot be turned wrong, but blades can be mounted at carb side by mistake as shematic says

 

[Hooty]

Re: Engine start rotation binding.

According To Spenceror, binding happens just before tdc. At that point, reeds and ports "out of the picture?". <br /> <br />Spenceror: How close is piston to tdc when it bind?<br /><br />c/6<br /><br />hooty

 

[Spenceror]

Re: Engine start rotation binding.

To: Schematic, G Dane and Hooty,<br />Thanks for the input. I don’t think the reed block has ever been touched by the previous owner, the paint on the nuts and gasket has not been scratched or chipped. The looking through the carb. the reed plate appears to be in correctly, just see a plastic screen, no metal reeds visible. Did I mention that when the flywheel key initially broke that the timing went out and the engine backfired. This is the first and last indication of the motor working since I bought it. Maybe it destroyed the reed plate or part of it is lodged in a port.<br />I measured the points where the pistons start to bind. They both measure almost equally.<br />ONE PLUG ALWAYS REMOVED FOR ALL TESTS. CANNOT MOVE WITH BOTH PLUGS IN.<br /><br />Excess pressure starts about 1 1/8inch from high point of piston to bottom of plug thread (1/8 inch) and remains until TDC is reached..<br />Excess pressure maintained at TDC with very little leakage, then flywheel moves easily at TDC until pistons starts downward movement.<br />Excess pressure maintained for 2 inches and then releases freely to bottom of travel at 2 3/4inches.<br />At TDC with compression the connecting rods had a little play while moving in both directions with pistons stationary. <br />Removed plug and inserted into other piston and got same results.<br />I repeated this many times to get a fairly accurate test result. <br />With both plugs out there is pressure building up and releasing behind the pistons while I rotate the flywheel. I think it is pressure or vacuum and not mechanical binding, but I will not assume anything now. <br />Thanks for the replies.<br />Spenceror<br />

 

[petryshyn]

Re: Engine start rotation binding.

is it possible that the head has been changed? Wrong head = high compression?<br /><br />Pull the reed plate and inspect. Inspect the screen for blockage. I've seen plastic used as filters which melted to a blob with alcohol.(spray carb-cleaner can do the same) Be sure you have no restriction in the intake while you're in there. Try with reed plate off as well......