1979 spirit/suzuki 85hp need help trouble shooting

[jmadoche]

i have a 1979 spirit 85hp. ran great till last weekend went out ran fine to fishing location backed off throttle and started missing and would not stay running. if i would start it in neutral with lots of throttle it would run on like one cylinder. got it home ran it with earmuffs and it started out missing bad then ran fine till it warmed up and started missing again. i checked resistance on all 3 coils and all reed the same so i don't believe it to be a coil. i played with it some more and it ran fine for half hour i took it for a test drive and started running on one cylinder again. pulled the plugs and #2 had carbon and #1 and #3 were wet. im suspecting the cdi unit. but any other input is appreciated before spending that much on something that i don't know for sure is the prob.

 

[Silvertip]

Re: 1979 spirit/suzuki 85hp need help trouble shooting

Check for spark on all cylinders. The carboned up cylinder probably killed spark on that cylinder. Perhaps just chaning plugs is all that's needed. If you have carbon coming loose, the engine needs a thorough decarb. This process is covered many times on this forum. Wet plugs would indicate weak spark. Compression check before and after decarb would provide you with an idea of the general health of the engine.

 

[jmadoche]

Re: 1979 spirit/suzuki 85hp need help trouble shooting

Check for spark on all cylinders. The carboned up cylinder probably killed spark on that cylinder. Perhaps just chaning plugs is all that's needed. If you have carbon coming loose, the engine needs a thorough decarb. This process is covered many times on this forum. Wet plugs would indicate weak spark. Compression check before and after decarb would provide you with an idea of the general health of the engine.

when its missing and i pull off those plug wires the motor runs the same. so i think that my #2 cylinder is the only one firing. but then it will purr like a kitten for awhile and then start missing.

 

[deejaycee_2000]

Re: 1979 spirit/suzuki 85hp need help trouble shooting

Check for spark on all cylinders. The carboned up cylinder probably killed spark on that cylinder. Perhaps just chaning plugs is all that's needed. If you have carbon coming loose, the engine needs a thorough decarb. This process is covered many times on this forum. Wet plugs would indicate weak spark. Compression check before and after decarb would provide you with an idea of the general health of the engine.

I agree with silvertip, change your plugs and follow the decarb process ... do a searh on decarbing there are alot of post here on it ... good luck

 

[jmadoche]

Re: 1979 spirit/suzuki 85hp need help trouble shooting

new spark plugs was the first thing i did. decarbing i think may not be a bad idea. but im thinking its the cdi unit because sometimes it works and somthings it does not and ignition coils all read the same on ohms so i don't think i have a bad coil. or maybe trigger coil assembly but someone said usually they go at once either it will run or it won't. any other idiea's?

 

[deejaycee_2000]

Re: 1979 spirit/suzuki 85hp need help trouble shooting

I really doubt it is the CDI unit but I could be wrong .... they hardly ever go bad .... have you done a compression test?

 

[jmadoche]

Re: 1979 spirit/suzuki 85hp need help trouble shooting

I really doubt it is the CDI unit but I could be wrong .... they hardly ever go bad .... have you done a compression test?

no not yet just had a buddy hold thumb over the hole and i pulled it over by hand and blew the thumb off all the cylinders said they all felt the same. but i will check with a compression tester tomarrow after work. i don't no how much compression i should have. i have a service manual but it only says the ratio.

 

[deejaycee_2000]

Re: 1979 spirit/suzuki 85hp need help trouble shooting

it should be about 110 - 140 psi if it is really good ....

 

[jmadoche]

Re: 1979 spirit/suzuki 85hp need help trouble shooting

it should be about 110 - 140 psi if it is really good ....

i checked compression tonight and i have 120 in all 3 cylinders but as quoted before it isn't the cdi box turned out that the carbon on the # 2 cylinder was because that carb. is messed up sprayed some gas into the carb when it started running bad and it picked right up so i think the float is sticking or the needle and seat is bad don't know if i should attempt to tear into it or take it in for that looks like a real pain to get it out.