no spark to cylinders 3 and 4

[radams]

I have a 1986 force 125hp and only cylinders one and two are fireing. Yesturday we swapped out the coil packs with 3 and 4 to see if it is those but they still fired when they were on cylinders one and two. We noticed that 3&4 are linked to one module (black box) and 1&2 are linked to another module (black box) would replacing this module cause any other electrical problems and would it fix the spark issue

 

[pnwboat]

Re: no spark to cylinders 3 and 4

Could be the module or the stator winding that supplies voltage to the module. Swap module 1 with module 2 ( they're both identical) and see if the problem moves. If so, it's the module. If the problem stays the same, it's the stator. Make sure you take the time to mark the wires on the modules before you disconnect them.

 

[mauiboy]

Re: no spark to cylinders 3 and 4

I did that with my 1988 85 hp but instead of swaping out the Module what i did was use a oms meter if you have 0 oms it is fine I forgot what mine read but I did not have to have the headace tring to remember what wire went to where.

 

[radams]

Re: no spark to cylinders 3 and 4

Half the stator is very hot could this be an indication of the stator being broken

 

[Frank Acampora]

Re: no spark to cylinders 3 and 4

No! half the stator supplies 12 volts AC to the rectifier. the other half supplies about 150 volts to power the CD boxes. Generating power generates heat, however, if there is a short, then the stator could get much hotter than normal. Check the two wires that power the box for #3 and 4. If it reads 0 or very low ohms, there is a short and the stator needs to be replaced. Normal resistance is, I believe around 700 ohms. If it reads infinite ohms, then there is a break and again, the stator needs to be replaced.

 

[boroutdoors]

Re: no spark to cylinders 3 and 4

I had a simular problem with my 85hp force. It ended up being the starter wasn't craning fast enough. If your starter is weak deal with that first.

 

[radams]

Re: no spark to cylinders 3 and 4

Ok we replaced the stator and have spark in all four plugs now but we are still not getting full power . What is a good way to check if we are getting gas into the carborators

 

[pnwboat]

Re: no spark to cylinders 3 and 4

Check your compression. You should have a minimum of about 110 to 125 LBs (ideally 145+ LBS) and no more than 10% variation between the lowest and highest reading. Then check the fuel pump diaphragm. If it has any signs of a hole or is stiff and deformed go ahead and replace it.

 

[radams]

Re: no spark to cylinders 3 and 4

How would I go about checking the compression

 

[pnwboat]

Re: no spark to cylinders 3 and 4

You need a compression gauge. It screws into the spark plug holes.

http://www.amazon.com/Flexcut-Flex-Drive-Compression-Tester/dp/B001UFVI8M/ref=sr_1_4?ie=UTF8&qid=1305350448&sr=8-4

 

[radams]

Re: no spark to cylinders 3 and 4

Ok compression is good and fuel is good but still doesn't have the power that we had could this be the timing. If it is how would I go about adjusting the timing

 

[radams]

Re: no spark to cylinders 3 and 4

Ok compression is 40 psi in 1,3,and 4 and zero in number 2

 

[pnwboat]

Re: no spark to cylinders 3 and 4

You should have a minimum of 110 to 125 LBS compression. If you are really lucky, I mean really really lucky, it could be a head gasket. I kind of doubt that with readings that low in all 4 cylinders. More likely you have bad pistons and rings. You need to remove the head to be sure.