1993 force 70 wont idle because it's missing

[bob-o p]

it was running fine then all of a sudden it quit and will not idle because it is missing a little. what can i check to see if it is firing correctly or firing at all?

 

[12Footer]

Re: 1993 force 70 wont idle because it's missing

Operate te engine until it warms-up real good. Then shut it down.<br />With engine off---Take a hand, and place it by each plug.If one is colder than the other, that cylinder isn't doing anything. Pull the plug,and check for spark. if the plugs have over 80hours, replace them,because they are due.<br />Note the condition of each plug.<br />Here, the manual will pay for itself ,and the information required would mean very much typing.<br />

 

[bob-o p]

Re: 1993 force 70 wont idle because it's missing

thank you i'll do that

 

[Mufasa]

Re: 1993 force 70 wont idle because it's missing

Sounds to me like you stuck a piston. Pull out the spark plugs and put your thumb over the spark plug hole. Rotate the flywheel by hand and feel for a vacuum pull on each cylinder. If one or more does not pull on your finger remove the cylinder head and inspect.

 

[bob-o p]

Re: 1993 force 70 wont idle because it's missing

thanks i'll do that too

 

[bob-o p]

Re: 1993 force 70 wont idle because it's missing

i checked for fire and compression, have fire (or some anyways)but no compression on top cylinder. i think the head gasket is blown BUT i changed it not very long ago, because it blew. what could cause this? by the way the first time was cause of salt water, or i thought it was, but it hasn't seen salt water since i got it, so it must be something else.

 

[12Footer]

Re: 1993 force 70 wont idle because it's missing

Hmm. Well, these engines have a weak area, the exaust port plates. They tend to warp when the thermostat sticks, or when the engine overheats, or the engine runs into quickly changing water temps, causing them to leak thru the exaust port plate gaskets, and into the combustion chamber.<br />A compression test won't allways fail in such a case, but if you have no compression, order the head gasket,plus a set of exaust port plate gaskets.<br />I pray you have no "holy-piston syndrome".<br /><br />Be carefull with torquing the bolts out, as they tend to "become one" with the block due to corosion.

 

[OBJ]

Re: 1993 force 70 wont idle because it's missing

Ditto 12footers suggestions. May be a good idea to pull the head first and check for "holy-piston syndrom" before ordering parts. I like that 12footer, "holy-piston syndrom". LOL!!

 

[bob-o p]

Re: 1993 force 70 wont idle because it's missing

i forgot to mention and it may not matter, when it blew before i could see the water on the plugs before i tore it down, but this time i can't see any water on them ,but i havn't tore it down yet.also could anything else cause it to blow?? i checked the cylinders before and they weren't scored and nothing looked wrong keyword "looked".

 

[OBJ]

Re: 1993 force 70 wont idle because it's missing

Bob..<br />From your post, it sounds like either the engine blew before or the head gasket blew before. If it's the head gasket, you may be dealing with a warped head. Pull the head and clean the gasket surfaces and put a straight edge along it. Also, if you have changed head gaskets before, did you torque the head to spec's from the center out?

 

[bob-o p]

Re: 1993 force 70 wont idle because it's missing

yes i torqued them by what the specs said, but i won't know much till i tear it down and start checking. thank you all for your help.