A warning about Engine timing.

[harbormaster]

One of the most overlooked items on out boats is the ignition timing. A perfect example of this is what happened to my 18's engine. It was running like a scalded dog....that is until pre-ignition destroyed a piston.

I bet a lot of us don not check out timing as long as the boat is running great. I know I did not.

With todays electronic iginitions and fuel it is wise to check your ignition timing. A quote from Lake George Performance Marine website states:

"Timing - Set to specs, not over 32 degrees total advance. You used to be able to run 34 degrees but with today's gas you run high risk of detonation at 34 degrees +."

I can attest to this....

[Dredgeking]

with the hp 500 we'd try to run it up to 36 deg. but we checked it often and always ran high octane fuel. it's cheap hp until you take it too far.

[mphatc]

Note of caution to those in the midwest . .

A friend recently lost an engine during the One Lap of America in the midwest. In the process of identifying the cause it was pointed out to us that the gasoline supply in the midwest is of lower octane !

This engine died from preignition . . detonation from to much ignition advance.

Be cautious where you buy your marine gas!!!

Mario L.
Now building a 300 hp 302 Ford for my boat that will run on marine pump gas !

[smoothie]

Harbormaster...I bet ya thats why you have flames shooting out your exshaust pipes eek! :D sorry I couldnt resist,but really your right,I have two witness marks on my distributor,one for good gas and one for dock gas,and its always a good idea to check your plugs every so often,they tell no lies...

[Capt. Donzi]

Mercury "blue motors" have Knock sensors....
you can run lower octane if you have to and it will not hurt it....you just wont get the performance

[Rootsy]

i can personally attest to the CRAP fuel here.. the oxygenated chock full of methanol good wholesome fuel.. yep... bout a year ago the ole 4.6 in the F150 began running like crap and spark knocking at low rpm under load... i am not the only one to notice this... i know a few other friends who have encountered this in their silverados...

you switch to 89 octane and the performance is back, fuel milage returns and so do the ponies...

I run 93 octane minimum in the 16 and 36* total by 2800 rpm on top of 9.4:1...

the most dire mistake you can make is ASSUMING your timing is correct... check it at least once a year, when you commission your motor is a good time... or setting it by "ear"... USE A TIMING LIGHT... every single time... a few degrees can kill you and you can hardly tell that small amount in the sound of the motor or on the tach... i dont know anyone taht can set it exactly by the "ear" method..

[rockindaboat]

like a old wise man once said TIMING IS EVERYTHING

[smoothie]

Rootsy,Just curious..what do you do when you cant buy 93 on the water.

[Rootsy]

i've never once run into it Smoothie... you can get premium on st. clair, you can get premium in kentucky... i can get premium at the gas station on the trailer...

so far so good...

guess we'll cross that bridge when we come to it eh

plus i just remembered that my MSD digital 6+ box has a high speed retard built in (plus a 2nd rev limiter and a start retard).. so i power that wire wrapped up there against the bulkhead with 12 Volts and put the dial on whatever i want to retard the timing and away we shall go...

so maybe i am prepared for once :rolleyes:

[smoothie]

Well there you have it wink now arent you glad I asked, :D one more for ya just because Im running about the same compression and timing,what is your oil and water temp.?

[Rootsy]

my water stays right where the thermostat opens... 160ish... well unless i and losing an impeller then it'll warm up gradually at WOT to 180 then my buzzer goes off and i shut her down... only had this happen once and that was on the GEN II...

i do not know what my oil temp is running... i was running straight 30 Wt valvoline but with the extra rpm's i am spinning running the SS these days and with the future cam swap i have moved to 20-50... i may go back to 30 once i get the HV oil pump installed...

with the 20-50 i run 50 psi cold at idle and 25 hot at idle... she shoots back to 50 - 60 above idle though...