9.9 outboard only turns 180 degrees left or right

I have a strange issue. Just replaced gaskets to exhaust manifold and cylinder head and when trying the pull cord to start, the engine only rotated a few inches. I took off the cord and tried manual turning by hand of the flywheel with spark plugs out and flywheel could turn roughly 180 deegrees left or right but not one full turn-seems like something is not letting the flywheheel turn-something inside hitting crank or pistons?Any ideas what this can be?

Re: 9.9 outboard only turns 180 degrees left or right

There is a lock on that engine which prevents it from starting if in gear with throttle opened. Put it in neutral and back off the throttle and see if it turns. Best of luck. Rick.

Re: 9.9 outboard only turns 180 degrees left or right

Not sure what year your motor is, but is there any chance you put the head on upside down? Most of them would be pretty obvious if you did, but some might not.

Any chance something was left inside the cylinder? An errant nut, piece of whatever?

Re: 9.9 outboard only turns 180 degrees left or right

Did you also replace the spark plugs? Maybe you put in new ones that had a longer reach, which could be now hitting to top of the pistons. Pull the plugs & see if it will give you a full rotation.

Re: 9.9 outboard only turns 180 degrees left or right

the machinist said:

Did you also replace the spark plugs? Maybe you put in new ones that had a longer reach, which could be now hitting to top of the pistons. Pull the plugs & see if it will give you a full rotation.

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Thanks to all for your advice-I took plugs out and head is in the right side up - its a 1993 model by the way-sorry. The one with the thermostat housing on top. I have to check the mechanical safety since I did not touch anything except the cables to get the exhaust plate and water jacket in place - its rigged with a steering and control box so the cables are a bit in the way when taking-out and replacing the gaskets at exhaust side. I have to go to the storage and revert. Thaks all again

Re: 9.9 outboard only turns 180 degrees left or right

Romain107 said:

Thanks to all for your advice-I took plugs out and head is in the right side up - its a 1993 model by the way-sorry. The one with the thermostat housing on top. I have to check the mechanical safety since I did not touch anything except the cables to get the exhaust plate and water jacket in place - its rigged with a steering and control box so the cables are a bit in the way when taking-out and replacing the gaskets at exhaust side. I have to go to the storage and revert. Thaks all again

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15/02.2013
Just carried-out some checks and finally discovered that the head gasket was wrongly supplied by the shop - to fit 1990 model not 1994 - therefore piston was snagging the top seal of the head gasket-lesson learned-always check before fitting I guess.-Cheers

Re: 9.9 outboard only turns 180 degrees left or right

thanks for replying with the cause and fix

Re: 9.9 outboard only turns 180 degrees left or right

You are all welcome - I found many articles which have helped me over the years but could not find anything about this new experience. Never crossed my mind to check the head gasket presuming the part number was correct. This is actually part of a much bigger problem however I started the diagnose in steps. My best friend needed a service on his Johnson 9.9hp and advised an impeller replacement was due. Sure enough the rubber parted the brass body so to me there was something else going on with this outboard. When I started the unit only exhaust came out of the telltale hole - What? so I checked the impeller function by use of a slow speed drill - result was fine (lower unit in bucket full of water and use of 6 inch copper tube exiting the water pump for testing purposes). Then compression which was also fine, then I reckoned corrosion in the exhaust side plates & water jacket-found salt blockages-cleaned all including head from salt ensuring water circulation without motor on was OK. after refitting all gaskets today retested water flow via lower unit and driller with hose connected from water pump to intake tube - water flow out of telltale and thermostat fine. Refitted lower unit & started the outboard only to get smoke again-therefore it must be the two grommets at the exhaust tube - exhaust gases & pressure not allowing water to get to the head - Access needs upper leg and engine to be taken apart so that's going to be fun......

Re: 9.9 outboard only turns 180 degrees left or right

PS-Cordless drill only can be used - water and electricity don't mix-caution anyone considering using this method described for testing of water pump.

Re: 9.9 outboard only turns 180 degrees left or right

Don't feel bad, as I have also been where you were, put a pre 93 gasket on a post 93. They will bolt on but the cylinders have a smaller bore so the larger 93+ piston kind of crunches the inner copper ring.

Re: 9.9 outboard only turns 180 degrees left or right

It could be a swelled up grommet where the upper water tube goes into the power head.