60 hp 4 stroke

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Arrie D

Senior Member
Came back from R B yesterday and after running for about 3 miles decided to change fuel to full tanks. Got back on the plain and kept on running - all of a sudden the one motor lost power. Stopped and checked the fuel lines - opened the cover but could not see anything wrong. Kept running with one motor not getting more that third its power. Stopped again pumped the fuel ball and bang, got bursts of power. Would run but could see on the ref counter that every 10 sec would loose power and then gain power.

Obviously some thing with fuel. Either a filter or a jet or water ?? As i say every time you pumped the ball she would go - so forcing the fuel worked ??

Any advise ?
 
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Patrick

Sealiner
Hi Arrie.Do you run both motors off one tank or individual tanks?

I would think if the problem only occurred just after you changed tanks, i doubt it will be a fuel pump, but rather something faulty with the connection or fuel line. If running individual tanks it could be sucking in air at the connection on the tank you swopped over to for that motor, for the problem occurred just after the change.

I once had a similar problem on my one motor where the primer ball also had to be pumped to feed the motor. Turned out to be a pinched fuel line further up after a boat shop had replaced the throttle cables. So yours pretty much sounds like a fuel starvation issue.
I would try filling the original tank you were running on and run the motor off that and see if it persists.Or leave the tanks as you have them now and swop the fuel lines at the motor connections and see if the problem now occurs on the other motor.
Good luck and report back.
 
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Breads

Senior Member
Definitely sounds like sucking air or fuel starvation as Patrick says. Other things to check are the O-ring where you clip the fuel-line onto the motor; and the vacuum advance hose on the fuel pump - mine had come off, giving us lower revs with a surge now and then. Worrying when it happens, but easy to fix.

Also been told not to use the cheaper GUD type inline filters, they don't always let enough fuel through.
 
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miles

Sealiner
Hiya

Pretty sure its a small problem. 90% of your engine troubles WILL come from fuel issues!!

Some things worth checking:

Is the fuel line kinked anywhere?

Is the fuel tanks breather open?

Do you have any filters in the fuel line? Chances are very good, that the filter is dirty and needs to be replaced. If i can recommend, but two RACOR filters, with water traps. They cost R700-1000 EACH, but is money WELL spent. I use a normal GUD filter, THEN a racor, THEN the fuel gets to the engine. Evey few months, just throw the GUD filter away and replace with a new one. They cost about R10-15 each, so its very cheap to buy and they do stop MOST of the dirt.

Open the motor cover and check the fuel bowl water trap to see if there is any water in it. Clean and replace.

It could also be that your fuel tanks fitting does not fit well with your fuel hose fitting, creating a poor connection that sucks air.

 

To find out EXACTLY what the problem is, you need to start a process of elimination. Its either the motor, or the fuel tank and fuel line. Simply unplug the fuel hose from the MOTOR and swap the port and starboard fuel lines around. If the problem still persists, its the motor that has a problem. If the motor that was running fine, is now giving your problems, after swapping the fuel lines around, it the fuel tank and fuel line system that needs inspection.

Swap fuel line back to the way they were originally. Now take a short peice of fuel line and connect the fuel take directly to the motor. If it runs fine, you have a problem with the original fuel line. If it doesn't run fine, the fuel tank or fuel tank fitting is the problem.

When the MOTOR is the problem, the only thing you can do is clean the filters inside the motor cover. Anything else, the dealer will have to sort out.....

 

Like i said earlier, sounds like a small fuel problem. Keep us posted!!
 
M

miles

Sealiner
Also been told not to use the cheaper GUD type inline filters, they don't always let enough fuel through.
Click to expand...
 

Breads, i use them on all my boats, from the small 5m semi-rigid all the way through to my 33'er with twin 225hp motors and they work just fine.

The problem is when you use them on 2 stroke pre-mix engines. When you pour two stroke oil into your fuel tanks, some filters work so well, that they will filter out the OIL from the petrol. Not good for your motors!! That said, i used them on my old commercial boat, with 2x85hp 2 stroke, pre-mix models and they worked fine. Replaced them every 3-4 weeks, but then we were fishing 4-6 days a week.
 
B

Breads

Senior Member
Thanks Miles
I think the bugger who told me was just trying to (and succeeded in) selling me his filters.
 
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Arrie D

Senior Member
Hi guys - thanks for advise thus far. I run the motors off separate tanks. I have no filters on the fuel line - only the one inside the motor. Will get a piece of fuel line tomrw and test. Cannot reach motors with others fuel lines.

Will keep you posted. 
 
P

Patrick

Sealiner
Just a thought Arrie, but if you run the motors on the muffs only you may not pick up if the problem has been sorted or not. Chances are it will take the motor pushing a load to show any real fuel problems.
 
W

will101

Senior Member
Patrick wrote:
Just a thought Arrie, but if you run the motors on the muffs only you may not pick up if the problem has been sorted or not. Chances are it will take the motor pushing a load to show any real fuel problems.
Click to expand...
that's right, my one motor revs like a demon in the yard but at sea it will not go over 3500. It takes more juice to keep the revs at load. I have 2 racor filters, but I'm also about to replace them and will also change all my fuel lines, PLUS add 4 GUD inline filters, as my boat has a network of fuel hosing, each motor being able to run off any one tank or both if needed.
 
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Arrie D

Senior Member
Ok - so yesterday I ran the faulty motor of a fuel line coming from the other motor.

Same thing - So now its either the filter or fuel pump or carbs ??
 
F

FishExcutnr

Sealiner
wierd, our 60hp merc reved perfect in neatral out of the water, put here in gear in the water and kept loosing power, would not go over 3000rpm, spent an entire weekend at breede with the mechanic who opened up and cleaned carbs, nothing worked, finally just replaced all spark plugs and she worked, same thing happened again, replaced spark plugs and runs perfectly. i know nothing about engines this just worked for us, something like not all the cylinders where firing in gear, might be talking a load of bull but it worked.
 
R

Royden

Senior Member
FishExcutnr wrote:
wierd, our 60hp merc reved perfect in neatral out of the water, put here in gear in the water and kept loosing power, would not go over 3000rpm, spent an entire weekend at breede with the mechanic who opened up and cleaned carbs, nothing worked, finally just replaced all spark plugs and she worked, same thing happened again, replaced spark plugs and runs perfectly. i know nothing about engines this just worked for us, something like not all the cylinders where firing in gear, might be talking a load of bull but it worked.
Click to expand...
Seems to me it might be over fueling under load. Throttle bodies are wide open with more fuel to air mixture going through to the cylinders. If the spark plugs are checked after a running the motor and they are black and wet, result over fuelling. Had many of bikes which I rejetted to get the correct buring colour. Normally an off white/cream colour is correct.
 
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patrys

Senior Member
blackbird had the same problem with his enjin. cleaned carbs,feullines,plugs. turned out to be the feulpumpcasing that had a crack in it.replaced it and problem solved.
 
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Arrie D

Senior Member
Had the boat in to Boat Anchor shop - found something like silicone inside fuel connector. Cleaned out and all sorted !!

Great - we on the go again !!

 

 
 
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Arrie D

Senior Member
'Silicone substance' - fuel cap rubber that fell into the tank !!!! Perished and got sucked up into fuel line !!
 
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