Ignition issue 2000 Mercruiser 5.0, V8 Thunderbolt IV ignition

[madurodave]

I am searching the forum for answers as well but thought I would post this question:

Ignition issue 2000 Mercruiser 5.0, V8 Thunderbolt IV ignition:

Just here recently, sometimes when I go to turn the engine over, I get nothing. If I turn the key back off, then to start again, it fires right up. I cannot get it to fire up everytime. And then the problem will hide itself and fire up several times in a row?

 

[Don S]

Re: Ignition issue 2000 Mercruiser 5.0, V8 Thunderbolt IV ignition

From your discription ("sometimes when I go to turn the engine over, I get nothing.") it sounds like the engine is not even turning over, if that's the case, up in the Adults only sticky is a thread on HOW TO troubleshoot your starting system.
It has nothing to do with your ignition system, that just gives you spark, nothing to do with cranking.
PS: you have a Thunderbolt V, not a IV on your 2000 model.

 

[madurodave]

Re: Ignition issue 2000 Mercruiser 5.0, V8 Thunderbolt IV ignition

please close this,. I found the answer. Thanks Don S!

 

[Alpheus]

Re: Ignition issue 2000 Mercruiser 5.0, V8 Thunderbolt IV ignition

Electric fuel pump? Fuel injected or carb?

 

[madurodave]

Re: Ignition issue 2000 Mercruiser 5.0, V8 Thunderbolt IV ignition

From your discription ("sometimes when I go to turn the engine over, I get nothing.") it sounds like the engine is not even turning over, if that's the case, up in the Adults only sticky is a thread on HOW TO troubleshoot your starting system.
It has nothing to do with your ignition system, that just gives you spark, nothing to do with cranking.
PS: you have a Thunderbolt V, not a IV on your 2000 model.

yes sir, on all accounts. I will do some testing now!

 

[180shabah]

Re: Ignition issue 2000 Mercruiser 5.0, V8 Thunderbolt IV ignition

OK Dave, so what was the problem and how did you solve it? Somebody else may develop the same problem and need the answer. Don't be stingy with the info.

 

[johndoe]

Re: Ignition issue 2000 Mercruiser 5.0, V8 Thunderbolt IV ignition

Just for information:
My 6.2L Bravo 3 had very similar problem... Once while anchored off an island in south puget sound, the engine would not turn over and I checked every wire, connection and fuse I could think of... could not get it working. Just before the BoatUS guy arrives, it just magically fires up... we head straight home. A few days later I discover the problem when troubleshooting according to the service manual... (check voltage between battery and starter) I had a significant voltage drop on the wire from the battery to the starter. Found the positive cable to the starter had come loose at the starter, thanks to that lousy plastic insulator they put on there... Turns out, it was never really tightened all the way! Since I removed the starter and secured all wiring and re-installed it, I have never had this problem again!!!

 

[madurodave]

Re: Ignition issue 2000 Mercruiser 5.0, V8 Thunderbolt IV ignition

OK Dave, so what was the problem and how did you solve it? Somebody else may develop the same problem and need the answer. Don't be stingy with the info.

well, can only be 2 problems. Will update once I fix. Promise!

 

[havasuboatman]

Re: Ignition issue 2000 Mercruiser 5.0, V8 Thunderbolt IV ignition

A faulty key switch will also cause those symptoms. Always check the simple stuff first!!

 

[Fishermark]

Re: Ignition issue 2000 Mercruiser 5.0, V8 Thunderbolt IV ignition

please close this,. I found the answer. Thanks Don S!

well, can only be 2 problems. Will update once I fix. Promise!

Dave - you are a man of few words! Like 180shabah says - share what you've found. Even the "2 problems" that it can be.

 

[madurodave]

Re: Ignition issue 2000 Mercruiser 5.0, V8 Thunderbolt IV ignition

sorry guys. Boat is in storage so I dont know for sure But ffter reading the sticky, it has to be the ignition switch or neutral safety switch. When I turn the key sometimes, I get no clicking or anything so I bet its the ignition/key switch. And again, other times it fires right up.

I will post the findings...when I find them

 

[Fishermark]

Re: Ignition issue 2000 Mercruiser 5.0, V8 Thunderbolt IV ignition

Another common problem can be the connection at the main engine harness.

 

[madurodave]

Re: Ignition issue 2000 Mercruiser 5.0, V8 Thunderbolt IV ignition

this issue was caused by a little corrosion on the key switch. I removed contacts and cleaned! Problem Solved!

Thanks Again, iboats!

 

[madurodave]

Re: Ignition issue 2000 Mercruiser 5.0, V8 Thunderbolt IV ignition

This problem is soo annoying! On the trailer to launch Friday night...just a click. 8 tries later, fires right up. NO ISSUES the rest of the night...I was trying to get it to NOT START again so I could do some further testing.

I get it home and tinkering around Saturday, I started this thing no less that 30 times to try and get it to act up again.

Of course, As soon as I have a boat full this weekend, it will NOT start and I will be screwed. I am thinking of just buying the Starter soleniod and the soleniod on the top of the engine.

809463A 1 and 89-96158T .

What are your thoughts? It has to be one of these causing the problem, right? Also, all connections are clean and tight. I would way 1 out of 50 times is will make one single click. Biut again, I can't get it to act up in the driveway..go figure.

 

[6meter]

Re: Ignition issue 2000 Mercruiser 5.0, V8 Thunderbolt IV ignition

Battery cable connections at the starter solenoid or the starter brushes.