needs a choke to keep going

[redneck joe]

Mostly.

1984 75 Rude.

Had a flat spot getting on plane early last season - i could feather thru it but got to the point where I had to kick the choke to get going. Had the criminals that operate the boat shop I used to give money to for carb rebuilds. Ran great rest of the season. Same thing mid season this year, getting worse. Runs fine when starting fro cold, pops up on plane, RPM's sound OK maybe a bit low (no tach). Then when I stop to chill for a minute it really doesn't want to get on plane and I have to hit the choke to keep it running at any decent rpm. Runs fine at idle - all 8 miles back yesterday. Oh and the 1971 6hp kicked on second pull and ran beautifully for a couple miles.


Interestingly when I got back to the ramp, which has a very small dock, there was a pontoon just sitting there. I waited for about 10 minutes a ways off thinking the truck would be pulling the trailer down shortly. Started to get pissed. Then as I drifted closer I saw the cowl off. Yep, broke down. Pulled up and started talking to them and turn out he was having the same issue on his Johnson 3 cyl. Forgot to ask the year.


So, thoughts? I did run a crap ton of seafoam thru it (yes bruce the snake oil) and the cold start / on plane is much better but the hot issue is same or worse.

 

[racerone]

Post results of a compression test first.

 

[F_R]

Some of us are experienced outboard techs. The inference that we are criminals is offensive and won't get you any help.

 

[redneck joe]

Some of us are experienced outboard techs. The inference that we are criminals is offensive and won't get you any help.

totally un intended. Funny, forgot how different the crowd can be on the same forum. I mostly talk about my below boat with the mercruiser and those folks are well aware of the local shop I'm referring to as criminals, and if you saw the pics of the work you would agree it is truly bordering on criminal.

So aplogies to you, completely unintended.

 

[redneck joe]

Post results of a compression test first.

forgot about adding that

~132 all three so completely fine, especially for this old of a motor - I bought from the son of the original owner, had a new lower put on is the only thing ever done to it.

 

[racerone]

Carburetors are very reliable and do not need frequent rebuilding / cleaning.-----If you go to a shop and ask them to " rebuild " the carburetors and there is no improvement you can NOT blame them !!--------So the 84 model 75 hp is shown with adjustable low speed mixture needles.------Have you learned how to adjust them to compensate for differences in fuel , local atmospheric conditions, yes or no ?

 

[redneck joe]

no

It did run better for about maybe 20 hours then has regressed to worse than before. As far as blaming them, it is way more than just this one deal and actually this was one of the better experiences I had with them.

What would have changed on the adjustments? I run a lean 50-1 since I almost never run WOT, always buy pure gas, highest octane form the same station. I also put in new plugs because I could. .30 gap, Champion per specs.

 

[cfauvel]

RacerOne et al......wouldn't having to choke (primer solenoid - Key IN) the motor continuously, point to the fuel pump ?

 

[F_R]

Carburetors are very reliable and do not need frequent rebuilding / cleaning.-----If you go to a shop and ask them to " rebuild " the carburetors and there is no improvement you can NOT blame them !!--------So the 84 model 75 hp is shown with adjustable low speed mixture needles.------Have you learned how to adjust them to compensate for differences in fuel , local atmospheric conditions, yes or no ?

I agree on the carburetors. If they do require frequent cleaning, it suggests to me that they must be getting fouled by dirty gas. Like from the boat's tank, not from the gas station.. Has anybody investigated that possibility?

 

[racerone]

The electric primer is a VALVE and not a pump !!-----So if the motor responds to the primer the fuel pump is providing pressure to the primer.----The primer puts fuel into the engine and this fuel bypasses the carburetors.----To me that strongly suggests a carburetor / adjustment problem.----But I can not see / hear / feel this motor and the owner has to trouble shoot.-----Should not be hard to figure it out either !!

 

[redneck joe]

I agree on the carburetors. If they do require frequent cleaning, it suggests to me that they must be getting fouled by dirty gas. Like from the boat's tank, not from the gas station.. Has anybody investigated that possibility?

no. Tank was part of a deal from a member here but ran fine the first 30 hours or so.

 

[redneck joe]

The electric primer is a VALVE and not a pump !!-----So if the motor responds to the primer the fuel pump is providing pressure to the primer.----The primer puts fuel into the engine and this fuel bypasses the carburetors.----To me that strongly suggests a carburetor / adjustment problem.----But I can not see / hear / feel this motor and the owner has to trouble shoot.-----Should not be hard to figure it out either !!

so imaging giving throttle to get on plane, and bogging down to sometimes dying. Hit the choke and engine sounds right. and gets going. Then starts bogging again and hit choke, stays good for a few seconds. Hull speed all day long fine back to ramp

 

[redneck joe]

In my mind I've eliminated clogged fuel line as it gets worse the warmer it gets.

 

[F_R]

I don't know who said this, but I love it: "Most carburetor problems are not". It usually is something else. I don't know the history on your motor, but one thing comes to mind. A sticky timer base will make some of the best mechanics swear it is a carburetor problem. If the timer base sticks, the carburetors will open before the timing goes to full advance and the result is exactly like a lack of fuel situation. And yes, temperature has a big effect on that stickyness. But as racer said, we are not there to witness it.

 

[oldboat1]

might add a water separating filter if you don't have one, particularly if using a permanent tank. Also a good idea to check for water or other contaminants. Pumping some from the primer bulb should pull from the bottom of the tank where water can lurk, or can siphon some up -- use the old glass jar test. Fuel will float on top after the mix settles out.

How's the operating temp.?

 

[redneck joe]

do not have a temp sensor but I could shoot it wiht my gun next time out.