"0" reading at idle Any Ideas?

[99z286spd]

I have a E88MSLESA It runs awesome but at idle my tach reads 0 or just above. At WOT I read 5400 which is what i tuned the engine for with the prop/trim. Idle though is nice and smooth and slow, but definitely not under 100 rpms. The rectifier is new(tested with MM before install), i checked connections and made sure the Tach is set at 6P.

Any Ideas?

Today was first time out since last season and I also noticed i have an issue with slow crank. I thought it was because of the high commpression (145 psi per cyl...just checked it) During that slow crank time I checked the cables at the battery to make sure they were tight(they were) and found that the ground cable only was very hot....???? After running the engine about an hour or so i shut it off and retried it.....same slow wiiirrrrpp wwwiiiirrrpppp vroooom. Last year I just touch the key to crank and it would fire right up cold or hot. ohh yeah.... and the battery is fully charged....it is kept on a batt tender.
Any suggestions ?
Thanks

 

[DJ]

Re: "0" reading at idle Any Ideas?

Remove the negative battery cable from the engine block and clean it. The bolt too.

That is your high resistance/slow crank problem. It may also be affecting the charging system/tach.

 

[emdsapmgr]

Re: "0" reading at idle Any Ideas?

Is your timing set correctly? Too much timing (when the engine is being started) also can sound like you have too much compression. You might load test the battery. Even though it's on a battery tender, if it has a weak cell-it won't put out the current you need for starting.

 

[99z286spd]

Re: "0" reading at idle Any Ideas?

Thanks gents.... I actually found my high resistance problem today. I did take the ground cable off the block yesterday and cleaned it and scraped it and reinstalled it. But during the process of testing to see if that was the cause....the starter completely quit.( It didnt crank any better either) I took the starter off the block and took it apart and found the ground motor brushes completely obliterated and not much left of positive ones. I went down to local marina and picked up a rebuild kit. I am back in business. I havent had it "running" yet to check the tach signal but while cranking to test the starter i noticed now it has a reading during crank of about 250-300 rpm..... it didnt before.

 

[99z286spd]

Re: "0" reading at idle Any Ideas?

Okay.....I took it out today with the wife. The tach is stil screwed up some how. It reads correct upon first startup and a while after but then after running for ten min or so,(or after WOT) the tach reads 0 or very close to it at idle.

if I bump the throttle it shoots up but the engine sounds like its going faster than what it reads.

Any suggestions?

 

[emdsapmgr]

Re: "0" reading at idle Any Ideas?

Still sounds like a faulty rectifier, but you just replaced it- so I'd borrow another tach and try that one.