Compression trouble cranking

[SNAPPERMG]

I'm trying to do a compression check on my 1998 90hp force. I followed all the procedures but I am confused on disabling the lanyard switch. Mine is an on- off switch that if I turn it off I get no cranks from the engine. If I go the other route and ground the plugs I get only about two turns on the engine and that's it. Obviously, the reading is not accurate with only two turns. Do I keep turning the key to get the 5 cranks or I'm i missing something.

 

[QuadManiac]

Re: Compression trouble cranking

The lanyard switch described is a push button switch which is depressed, enabling the ignition system, when the plastic end of the lanyard assembly is inserted into it. Pulling the lanyard from the switch disables the ignition, so if you have the lanyard attached to your clothing, and you get thrown overboard, the engine will stop and not run merrily along at WOT without its captain.

For the compression test, removing the lanyard from the switch disables the ignition so you can crank the motor over as much as you like, without generating any spark. Once ignition is disabled, turn and hold the key in the start position to crank the motor through at least 5 full crankshaft revolutions to measure the compression. More revolutions is better. Five, typically, is enough.

Regarding the 'other route', if you ground your plugs or plug wires, why can't you crank the engine all day, just as you would be able to with them connected normally but, for instance, out of fuel? You just hold the key in the 'start' position long enough to keep the motor turning through at least 5 revolutions.

Good Luck!

 

[baxtr]

Re: Compression trouble cranking

5 cranks at one time, not 5 turns of the key one crank each. If you are saying that the starter stops after 2 cranks even while holding the key in the start position, then check your battery, if batt is ok, then starter.

 

[SNAPPERMG]

Re: Compression trouble cranking

That's my problem. I turn the key and only get two cranks. The battery is charged and I replaced the starter last year. Come to think of it whenever I start the motor I can never keep it cranking. It's always a couple of cranks if it does not start then I need to start over. How can I go about cleaning the starter? I hate to go get another starter if I just replaced it last year. Could it be something else?

 

[QuadManiac]

Re: Compression trouble cranking

So you hit the starter position on the key switch and the starter will crank the engine over about 2 revs and then the engine stops turning. Then what? You let go of the switch and do it immediately again, or do you have to wait a bit before the starter will turn the engine over again?? When and under what circumstances did this symptom begin?

Additionally... why are you doing a compression test?

If it will only turn over twice before the starter stops turning it, it certainly sounds like a starter/solenoid/battery/starter wiring issue unless a bearing is siezing or it's somehow hydrolocking (fuel lock?).

If you continue to hold the start switch, does the starter make any noise or get hot?

When's the last time you had this engine running properly?

 

[SNAPPERMG]

Re: Compression trouble cranking

I think I solved the cranking issue. My battery has only a 525 MCA, while the owners manual has 630 MCA. I will upgrade the battery and see if that works.

QuadManiac- I'm doing a compression test because I have been having lots of trouble with engine stalling and hesitation on increase in throttle. I will set up a new thread and try to explain. Thanks for all your help.