Thunderbolt V 1999 5.0L high rpm ping

[chiefalen]

Re: Thunderbolt V 1999 5.0L high rpm ping

Champions is what i have in my 76' evinrude 70 hp.

Looks and runs like brand new.

Never touched salt water.

 

[jy118lfd]

Re: Thunderbolt V 1999 5.0L high rpm ping

Swapped in 8 NGK BPR6EFS


NO PING.


Still at 8BTDC Not 10

35.4 knots (40.7 mph) Wot hitting the rev limiter Not bad for a 305


I will run it with a full load on Friday or next Tuesday

I did not map the timing. I was alone. Tomorrow I will run it with a friend driving and map the timing.

I am going to do all that we talked about and post it here so it will help anyone.

The TR6IX iridium plugs seemed to have more of a projected nose than the BPR plugs. That combined with the finer electrode may have gotten too hot and caused the preignition. I am still going to add some fuel on the top and see how it reacts.

 

[chiefalen]

Re: Thunderbolt V 1999 5.0L high rpm ping

I am glad you found the problem.

Back to the basics.

Were any deformed?

Good luck go catch some strippers.

 

[MikDee]

Re: Thunderbolt V 1999 5.0L high rpm ping

Interesting, I see no advantage to iridium plugs other then for super longevity? I've read they don't conduct electricity as well as platinum, and that standard copper core is the best, besides In a boat they're usually not that hard to get at to change. Surprisingly they're projected nose, plus have that finer tip, that must be it. Glad you found the problem.

Does hitting the rev limiter mean your turning over 5100rpm?

 

[chiefalen]

Re: Thunderbolt V 1999 5.0L high rpm ping

I was thinking that also.

But he says he doesn't do wot often.

He uses it for fishing.

I just got a used prop, 17 pitch ill be trying out tomorrow.

And i won't be going wot.

Just want to see what speed i'll get at 2500-3000.

Been using a 15 pitch. That one with the new/old motor gives me at 4600 31 mph. Thats confirmed with a gps.

He ran into the problem with testing a prop i believe. Pinging at wot.

 

[jy118lfd]

Re: Thunderbolt V 1999 5.0L high rpm ping

Ran it Today From 6am till 11am

I timed the motor and get this 22degrees btdc at wot about the same at cruise. I would have thought it would have been at least 30. I did this with an advance timing light that I trust. Now the 22 would be fine if you added the 8 base, but that is not the case. It runs great though.


I think the rev limiter is set at 4850 or 4900 being the top rpm is 4800. I would love to have a 5100 rpm rev limiter to see what the boat would really do.

I may have to try a 19 pitch prop cause when I run wot it hits the rev limiter and I have to back it down to stop. I checked the secondary plates when my bud backed down to stop it from hitting the rev limiter and the plates were open only about 15 to 20%. There is more power in her.


I also tried raising the secondary metering rods while running wot and it seemed to bog the motor so I think I will try the smaller rods but will not need them.

 

[jy118lfd]

Re: Thunderbolt V 1999 5.0L high rpm ping

I am glad you found the problem.



Were any deformed?

Good luck go catch some strippers.

No none were deformed. In fact they all showed a light tan coloring confirming the air fuel mix is right. They also had no signs of detonation. Ie specks on the insulator, or over heated tips.


We got 4 bass but they were all 26 to 27 inches and a load of blues

 

[chiefalen]

Re: Thunderbolt V 1999 5.0L high rpm ping

Friend went today got skunked, nothing, nada, not a bite.

 

[chiefalen]

Re: Thunderbolt V 1999 5.0L high rpm ping

Pss where you get the bites i won't tell anyone.

Com-on taking my 13 year old son he needs a fish.

 

[jy118lfd]

Re: Thunderbolt V 1999 5.0L high rpm ping

Pss where you get the bites i won't tell anyone.

Com-on taking my 13 year old son he needs a fish.

About 5 miles south of Squan inlet in 70 ft of water. You will see the birds.

 

[jy118lfd]

Re: Thunderbolt V 1999 5.0L high rpm ping !!!!Update!!!!

Re: Thunderbolt V 1999 5.0L high rpm ping !!!!Update!!!!

I ran the boat last tuesday. We made a bass and bottom trip. I put about 6 hours on it mostly idle trolling for bass. On the way back to port I decided to run it wot. It seemed ok until about 30 seconds of Wot. Then it nosed over and leaned out. I backed out of it and then went to Wot again to see. Only using 17.8 gph wot and nosing over. I ran back at cruise and decided it was late and I would check it out later. This morning in the rain I pulled the pickup tube in the tank and checked for obstructions. The tube was clean, the antisiphon valve was clean. I moved foward and checked the next in line my floscan transducer. Clean as well. I had swapped the seperator filter only a week or two ago and it did not help. So I was confident that was fine. I pulled the carb filter and remembered I had the paper filter in there. I was going to get the plastic one and never did. I took it out and opened it up. It did not look clogged but had some silt on it.

I took the boat out and ran it to check it out.

I was suprised to see 24.7 gph at wot. It actually was a little on the rich side as it was a little sluggish upstairs.

I figure the plugs stopped it from pinging when it was on the edge of too lean with the restricted fuel filter. Till it got WAY to LEAN to even make power.

I am going to reset the timing and run it then take a little fuel out and run it again. Oh and I will never use the paper filter in a marine carb again. As I did not get that much fuel when the filter was new. THE ONLY RESTRICTIONS IN THE FUEL SYSTEM SHOULD BE IN THE CARB. The rochester is a great carb but with the small fuel bowl it is imperitive for the fuel system to keep it full.

 

[MikDee]

Re: Thunderbolt V 1999 5.0L high rpm ping

Do you mean all this was because you didn't have the required marine plastic carb filter? it figures though, that would have been one of the 1st things I would have checked. So be it, I'm glad you found out what it was, Good Luck

 

[jy118lfd]

Re: Thunderbolt V 1999 5.0L high rpm ping

Do you mean all this was because you didn't have the required marine plastic carb filter? it figures though, that would have been one of the 1st things I would have checked. So be it, I'm glad you found out what it was, Good Luck

Yea I think it was. I did not remember putting it in there. It was the middle of the winter when I did the carb and forgot I even put the filter in there. It is not really needed with the merc seperator filter anyway.

 

[chiefalen]

Re: Thunderbolt V 1999 5.0L high rpm ping

Jeez you running in the rain over here.I was already to go this morning, thank G-d my son didn't want to get out of bed and my friend was hung over.

So i threw the tarp back on.

Poured here.

Glad you found the problem if indeed it is the problem.

Basics, basics. You started from the tank backwards. But you found it.

 

[jy118lfd]

Re: Thunderbolt V 1999 5.0L high rpm ping

.

Basics, basics. You started from the tank backwards. But you found it.

I found it for sure. The reason I started from the tank was to check the entire systen so nothing was missed. So I went to the pickup and worked my way foward. Only took about and hour to check the entire system for obstructions.

I really checked the tank vent first, so I really started from where the fuel goes in the tank.

 

[chiefalen]

Re: Thunderbolt V 1999 5.0L high rpm ping

Good move, if your on the bay tomorrow give me a shout 68. I'll be at the hook.