60 hp on a 20 ft pontoon = 13mph @ wide open???

[BillP]

Re: 60 hp on a 20 ft pontoon = 13mph @ wide open???

You're having to pump the bulb to keep fuel pressure...the hose is new...are the connectors and bulb new? If not it could be something simple like a bad o-ring on one of the connectors...and you can't see the air leaking unless there's a clean inline filter to watch fuel flow.

 

[samo_ott]

Re: 60 hp on a 20 ft pontoon = 13mph @ wide open???

If we get back to basics here. How did it run before the new carbs? Fine or poor? What was the reason for the upgrade? The high speed nozzle cracks? What is the compression on all cylinders and check the spark! Remove 1 wire at a time to see if the cylinder is contributing.

 

[kenmyfam]

Re: 60 hp on a 20 ft pontoon = 13mph @ wide open???

Still need answers on how it was before you did the work to it, did it used to be better ??, WOT what RPM you are getting, prop diameter and pitch, motor height, how is it trimmed and have you adjusted trim settings and what if any difference did it make.
Bottom line is that if the motor is not set up correctly for your outfit your performance will suffer greatly. Similar to trying to cycle uphill in top gear !!!

 

[R.Johnson]

Re: 60 hp on a 20 ft pontoon = 13mph @ wide open???

When you do get that engine running properly, make sure you have the correct prop that will put the RPM's where they belong. Any outboard I have ever taken apart that was run on a pontoon looked more like an old stove inside than an engine.

 

[mstrud]

Re: 60 hp on a 20 ft pontoon = 13mph @ wide open???

so here's the update. It isn't gettin up to WOT, because my top cylinder is dead, it has spark but it has no compression whatsoever. the bottom two are 130ish. I'm thinkin it's the reids, i dont know. I only guess that because there's no compression at all. This was my worst case scenario, and could certainly expalin the dysfunctional fuel pump. Anyone have any suggestions?

 

[wilde1j]

Re: 60 hp on a 20 ft pontoon = 13mph @ wide open???

If compression is zero, it sure isn't reeds. Blown head gasket, burned piston, broken rings, scored cylinder are likely choices, not reeds. BTW, when a cylinder is lost, you need to determine the cause, or it will happen again if you rebuild.

 

[steelespike]

Re: 60 hp on a 20 ft pontoon = 13mph @ wide open???

Absolutely no compression oh oh.I think its time to pull the head and look around.If its the gasket you'll be half way there if its piston/rings etc you can decide where to go from there.

 

[BillP]

Re: 60 hp on a 20 ft pontoon = 13mph @ wide open???

Might be a bad head gasket giving low compression but a burned piston can do that too...from a lean mixture or crud built up from running too cold or too rich. It holds heat and burn holes in the crown. Those results are what can happen from not decarbonizing. Forget the carbs...pop the cyl head off and look at the piston crown and cyl walls.

 

[Lakester]

Re: 60 hp on a 20 ft pontoon = 13mph @ wide open???

ms sed:

"so here's the update. It isn't gettin up to WOT, because my top cylinder is dead, it has spark but it has no compression whatsoever."

have been following this thread... sounds like u may be getting close to problem... sorry to hear. hope solution is simple,

regards
lakester

 

[mstrud]

Re: 60 hp on a 20 ft pontoon = 13mph @ wide open???

yeah, ok as i suspected the boat i bought wasn't the boat i thought i had bought. Oh well, lesson learned, test the compression, spark etc. of every motor i buy from hence forth... unfortunatly i wouldnt have bought the test gear until i had a motor with a problem... oh the irony... Anyone reading this please invest in a compression guage b4 your next used motor purchase if you havent already. As you can tell im pretty thrifty... so i wonder... Since i put the new carbs on and it fires right up now (chokes on the first crank everytime), i know its running inefficiently, but whats the motor life to be expected with this kinda problem if i was to keep on running it as is? I know it doesnt run ideally but is it only a matter of hours before the motor totally self-destructs on me, or is the dead cylinder not really gonna do much more than steal a little power? I didnt pay much for the boat, i know why now, but if i could get a few years of trouble free operation from the boat i dont care if the motor locks up three years from now... WWTSMD??? What would the savy mariner do??? Savy Mariners... your opinions please.

 

[tashasdaddy]

Re: 60 hp on a 20 ft pontoon = 13mph @ wide open???

fix the motor, it could blow the next trip out. you are over working the working cylinders.

 

[samo_ott]

Re: 60 hp on a 20 ft pontoon = 13mph @ wide open???

I wouldn't use it. The engine could grenade at any time. Expecially if the rod has let go on that one cylinder.

 

[carpenterken]

Re: 60 hp on a 20 ft pontoon = 13mph @ wide open???

If it is only the head gasket, it's a very easy and cheep fix.
I had a head gasket go when weeds got wrapped around my water intake and the motor overheated. New gasket and she ran like a champ.
Remove the head and check it, you have nothing to loose.

 

[BillP]

Re: 60 hp on a 20 ft pontoon = 13mph @ wide open???

I ran a 140 omc maybe 50 hrs with one cyl showing 30lbs of compression. I couldn't tell the difference except for power loss and rougher running.
The three good cyl plugs didn't show anything different. Btw...I popped the head off and found a pinhole in the piston crown. I have a 3cy OMC and running one less cyl will show up way more in performance loss than a 4 cyl though.

bp

 

[kenmyfam]

Re: 60 hp on a 20 ft pontoon = 13mph @ wide open???

I am thinking you take the head off and have a look to see if you can find what is causing the lack of compression. (broken rings, hole in piston, meltdown etc)
Let us know.