Motor trouble

[MIKE BURGESS]

Well I will be the first to admit it im not a motor head !!!!!!

Im still having the same problem as the other day the boat boggs down when I go around 20 knot or better.

Heres what I have done so far

1. Changed all the fuel filters
2. Checked 1 plug and it was fine but I didn't replace all of them yet.
3. Added gas cleaner to the boat.
4. Cleaned the carborator out
5. Replaced the air hose from the fuel pump to the carborator
6. Checked the points

Need help bad I can't stand not fishing.

Any suggestions would be appreciated big time.
305 motor w/4 barrel carborator 230 hp

Mike B

[Grady23]

Have you checked the in-tank fuel pickup tube? If the screen is partly blocked, it will cause this kind of problem. Do you have any way to check your fuel pressure? How old is your fuel pump? This sounds crazy, but check your oil to see if there is any gas in it? On old chevy blocks, when the pump diaphram went bad, it would dump gas into the crankcase.

[BARNACLE BOY]

i had a similar problem with my 350 chevy and it was only going up to about 2000 rpms and then it would bog down and the problem was a restriction in one of my fuel lines so check ALL of them( from tank to pump and pump to carb) take them off and blow them out if not that i would go to filters( front of carb and the stone in the pump if you have it and water seperator) if not that then pump by then youll have a new fuel system

[Bob H.]

Looks like you're still busy Mike.
1. Critters in fuel tank vent (bee's are problem this time of year)
2. Kink in fuel line or other obstruction. Get a see-thru fuel filter from an auto parts store and place between fuel pump and carb. Have someone watch for flow change. I doubt these are legal to leave installed.
3. Float levels (if your carbs have a sight glass your helper can monitor this in conjunction with #2).
4. Vacuum lines to carb - replacement is easier than finding a leak
5. Carb cleaning. You definition is probably different than mine. Complete disassembly, clean with compressed air, reassembly with new gaskets and float/needle valves (is this a Holley or Quadra Junk?)
6. Fuel pump pressure (#2 should exclude this unless decreased flow is obvious)
7. If it's backfiring you'll need to check timing and valve train.

[mikie]

Maybe your timing isn't advancing - assuming you have a strictly mechanical advance (marine) distributor - check your timing weight springs to see if they're rusted away. (under the points plate). You could put a timing light on and watch the timing marks as you speed up the motor - timing should advance.

[MIKE BURGESS]

Thanks guys im going to head down the boat like Mon/Tue and give all this a try, hope one of these things will fix it.

Again Thanks,Mike B

[billfish]

If you are saying won't go over 2000 rpm. I would say timing is too retarded, or points are not set right. If engine gets warm and it starts to bog - misses it could be your condenser. It happened to me , Took awhile to figure it out.

[3bees]

If it pops back it is probably ignition. Also if it pops back you could suck back water into engine. I had ignition problem this spring that would come and go. Got brand new dist. with coil and wires for chevy v8 $220.

[stevej00]

Mike,

Is the engine fresh or raw water cooled ?...And have you ever had the heads and exhaust manifolds off ? And about how old is the engine and major components.....My father had issues with an older 350 dieing out after a while and the I beleive that it came back to an exhaust manaifold issue. I can ask him and post. I know he always was tinkering with the mechanical timing too and always annually resetting greasing and adjusting points.


I'd check out the fuel reccs too....

[MIKE BURGESS]

THANKS EVERONE MOTORS FIXED bad spark plugs!!!!!!!!!!!!

[stevej00]

Awesome....time to get fishin....[grin]

[stevej00]

Mike,

Do you know if the new plugs matched the old plug's heat range ???

[MIKE BURGESS]

No I had a mechanic check them and recomended a bifferent plug we'll see in about a few runs how they hold up !!!!!!!!!!!!

[Seahunter]

Mike,
Something is wrong. To have the #5 and #6 plugs both go bad isn't coincidence. You said the plugs where trashed, how so?

[MIKE BURGESS]

Just worn out bent over to much heat the mechanic said. These plugs were replaced at the beginning of the year with the manufacture's recomended plug but the repair guy said these were the wrong plugs for this motor.
Actually I though the same thing 5 and 6 going bad might be something else.

What do you think it is???????? Don't want to trash the motor if it could be something else.

[Harry]

Mike I had the same problem a few years back with my inboard. Turns out the carb needed an overall. If it's a Holley they need a good cleaning once in a while.

[Seahunter]

My initial thought was the same as Harry's but after hearing the plug’s condition I'd also check everything out in the cooling system. The back cylinders typically run hotter than the others but a cooling problem will exaggerate the condition and cause problems also.

[reelclass]

I Have A 24' Grady White with the same type of promlem. I have twin 130 yammahas. The one engine runs great but i cant seem to keep the other engine running. it will run if i keep choaking it but when i am not choaking it it will bog out. Dont no what the problem is. I already replaced the sparkplugs and the fuel/water seperators. Any help at all would be helpful
Thanks James

[Grady23]

ReelClass --- Your description indicates fuel starvation. Be sure to check the small in-line filter and make sure it's passing fuel. You may also have junk in the carbs.

[reelclass]

Thanks Grady23 I think we found the problem it looked like I had a carb that would not open up when i gave it throttle. That should do it. I did take out the small fuel filter and cleaned it.
Thanks for the Information.

[MIKE BURGESS]

Well I have been out 9 times so far and checked the boat runs great, checked the plugs and they look brand new.
I also switched over to high test and it seems to be running better now then it ever did. Thanks for all your guys input was appreciated very much.

Mike B

[stevej00]

Awesome, glad to here !!