when to know fuel isnt getting to a cylinder...

bob johnson

Rear Admiral
Joined
Feb 25, 2009
Messages
4,306
after reading here for 6 months about blown motors and their causes...

it seems over heating and no oil are the most prolific causes.

I have added a water pressure gauge to my boat and I have added a temperature gauge, and I have run two wires to pull feeds off the senders( only have one now...sooo hard to find) and i can toggle the gauge back and forth between the senders to check the temp of each head..

all to make sure i dont let a problem get worse with out knowing.

Next I think about a clogged carb....either fully or partially were I am not getting enough fuel/oil into the cylinder..

and it isnt showing up from hearing the motor run..(V4) because the other 3 cylinders are carrying the load...and because the motor is so noisy already.

so how can you Check that the proper fuel is getting to the cylinders( I will always pre mix my oil with the gas)??????

I have never had a blown motor( knock on wood) I have run an 18 HP for three years, a 30 HP for seven years and a 50 hp for six years....

I just put the oil in...never had the carbs worked on...

but these bigger motors , i hear a lot about them going bad

I am running a 115 ocean Runner right now...V4..

i want to make sure i dont have problems in the future

thanks

bob
 

iwombat

Captain
Joined
Jul 12, 2006
Messages
3,767
Re: when to know fuel isnt getting to a cylinder...

A couple of things will tell you.

1) You won't get to full RPMs, for what I hope are pretty obvious reasons.

2) Your plugs will not have that healthy light toast colour, but will instead be white and possibly have damaged electrodes.


It's a good thing to look at your plugs occasionally. They'll tell you a lot about the health of your motor.
 

gsyfishy

Petty Officer 2nd Class
Joined
Apr 25, 2008
Messages
173
Re: when to know fuel isnt getting to a cylinder...

If your as handy and meticulous as you sound, cleaning and rebuilding the carbs with a manual, should be a piece of cake. And the plugs will tell you lots of things about each cylinders performance.
 

Johnny Too Bad

Petty Officer 2nd Class
Joined
Jul 21, 2009
Messages
107
Re: when to know fuel isnt getting to a cylinder...

It seems to me the vast majority of people who have experienced a blown motor are usually the ones that do not perform regular maintenance (replacing the impeller every two years, proper winterization, etc.) or don't run their outboards with the right fuel mixture. Obviously there are exceptions, but properly maintained, most outboards will run for many years.
 

bob johnson

Rear Admiral
Joined
Feb 25, 2009
Messages
4,306
Re: when to know fuel isnt getting to a cylinder...

A couple of things will tell you.

1) You won't get to full RPMs, for what I hope are pretty obvious reasons.

2) Your plugs will not have that healthy light toast colour, but will instead be white and possibly have damaged electrodes.


It's a good thing to look at your plugs occasionally. They'll tell you a lot about the health of your motor.

if you cant get to full RPMS one day and knowing you dont always run full RPMs, how much damage are you ALREADY doing running the motor for a day, once in a while TRYING to get to full throttle not knowing what the issue is..

bad gas....bad filter...

have you already ruined that motor by the time you get back to the dock???( ie scored a cylinder maybe...

it seems that a carb doesnt get clogged if the motor is used often and you have the proper fuel filters.

I have a fuel seperator, an Inline fuel filter.. and the fuel pump has that screen on it so i have tried to keep the fuel pure three ways , plus i purposely built the boat with dual PORTABLE tans..that can be removed and thoroughly cleaned or disposed of easily.

bob
 

gsyfishy

Petty Officer 2nd Class
Joined
Apr 25, 2008
Messages
173
Re: when to know fuel isnt getting to a cylinder...

Keep doing what your doin, if I put that much thought into making sure I did'nt blow my motor... I'd start kayaking!
 

bob johnson

Rear Admiral
Joined
Feb 25, 2009
Messages
4,306
Re: when to know fuel isnt getting to a cylinder...

Keep doing what your doin, if I put that much thought into making sure I did'nt blow my motor... I'd start kayaking!

If you used your boat in Long Island Sound in the Dec, Jan, and Feb at below zero temps, with seas possible to 10 feet, like I do, you might give your Kayaking start a second thought.

bob
 

jonesg

Admiral
Joined
Feb 22, 2008
Messages
7,198
Re: when to know fuel isnt getting to a cylinder...

Guys who seem to have gobs of bad luck with outboards are ez to spot when you read mssgs regularly here..

"motor started making noise so I put it in neutral and revved it to 4K....

took it out every day but it didn't "get better"

buzzer keeps going off so I disconnected it...

smelled something burnt but engine still runs strong so we kept skiing..."

sometimes they just let go but just as often they're beating you to death with red flags that theres something wrong.
 

iwombat

Captain
Joined
Jul 12, 2006
Messages
3,767
Re: when to know fuel isnt getting to a cylinder...

Correct!

If there's something not right you limp back to the dock and fix the darned thing. There's not a whole lot of minor failures that won't survive a dose of low-speed limping. If you let the minor problems go, they become major failures. Then, you have real problems.
 

petryshyn

Commander
Joined
Oct 3, 2001
Messages
2,851
Re: when to know fuel isnt getting to a cylinder...

A couple of things will tell you.

1) You won't get to full RPMs, for what I hope are pretty obvious reasons.

2) Your plugs will not have that healthy light toast colour, but will instead be white and possibly have damaged electrodes.


It's a good thing to look at your plugs occasionally. They'll tell you a lot about the health of your motor.

I completely agree with this. Your tach is your first defense along with your well maintained warning system. The tach is a "must have" and should be monitored at each and every WOT interval. I always recommend to do a brief warm-up and then go to WOT just to see the RPM reached and how it behaved getting there. The RPM reached will let you know to limp back or continue on your way.

Avoiding WOT is much more dangerous as it has no benchmark to compare to, and a lean cylinder can easily go undetected.....

Cheers....:)
 
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