40 hp merc

[clint]

ok so long time lurker first time poster...........

so here's the story, about 2 weeks ago i bought my first boat. a 1978 14 foot starcraft runabout with a 40 hp mercury, not the most condusive to fishing but its fun and it floats and i'll fish out of anything, plus i got it for a song.... beggers can't be choosers right?

so the guy i bought it from thought that the water pump might be going on it, and after a very very short test run once we were home with it i found this to be correct, so oh well off to the shop... 3 days and $107 later i had my boat back and couldn't wait to get out. spent the first weekend out on the water last weekend with the girlfriend and everything worked like a charm, well everything except the fish, but thats a whole other story.

so we spend the first 2 days out and everything is fine, monday comes along, the girlfriend has to run off to peterborough for the evening so i decide to go out and get a little fish time in, again everything seems to be fine until i hit some choppy water, the same choppy water that i had just spent the last 2 days on (mississippi lake) when all of a sudden i start stalling out everytime i crest a wave, this was a little disheartning but i could get it started right away again so it wasn't that big of a deal, i start to make my way back to the launch.... very very slowly...

once home i start going over things, I am by no means a mechanic but i'm not useless either, i find that i am able to turn one spark plug out with my fingers, so i fix that. i was aware of a slight kink in the fuel line that i was able to open up a little bit more before we went out the first time so i check that, still just a slight kink not enough for a total blockage. the third thing i figured out was a pure rooky mistake, i forgot to open the valve on my gas tank. so with those 3 problems found and rectified to whatever extent was needed or in the case of the kink whatever i could we head out last night to try for some better fishing. at first it seemed ok then the stalling started to happen again.... not to the extent that it was the first night but still a little bit anyways.

my experience is limited and i'm hoping that someone here might have some ideas about what it might be...

[plncrzy]

fuel pump? filter? both? ... If the water pump was neglected, I wouldnt be surprised if the the rest of the motor was neglected as well. I would buy a diaphram kit for the fuel pump and replace the fuel filter.

[clint]

i'm not trying to fight your help here, i just don't understand why this would be the problem when on smooth water it runs fine? i only have this problem when i hit rough water? like i said i'm not an expert by any stretch of the imagination so any help is greatly appreciated just confused is all.

[moonshine]

that is puzzling, i would start by checking for loose wiring. fuel filter would be a cheap and easy fix. even though it would have little or nothing to do with your problem, you may as well do it. another thing you could do is use some seafoam. it could be a fuel problem but i doubt it would be fuel pump. a good engine clean up with the seafoam should be done anyways. could be lots of varnish build up in the carbs.
good luck and keep us posted.

[cprince]

Due to recent events, I will preface this and any advice I give: I am not an expert. Bring your motor to a professional, not some inbred village idiot stonner with a GST number. Go to a marina.

That being said, I think that it is the carb. Specifically the float. Perhaps it is not properly seated and when you hit rough water it either lets in too much or not enough gas (Too lean or rich). If you are brave enough to break open the carb and rebuild it, I think you will have solved your problem.

Again... I am just a back yard hack. That water pump would have cost you.... well... I don't know Merc prices... but I can guess that it would not be more than $20 for an impeller $50 if you had to replace the housing. It would have been done within an hour. And the best part would be you fixed it yourself.
My 'Rudes cost me $23 for complete pump rebuild kit. My old "Off Brand" cost me a lot more at $60.

Don't be frightened to get grease under your fingernails. Keep posting and I, for one, will keep trying to help.

Craig

[clint]

thanks for the quick feedback.......
and don't worry, reading through the pre-detonation thread i was on your side, so if i happen to blow my motor while working on a suggestion from any one here, i will for sure take the blame squarely on my own shoulders
like i said any help is appreciated.

i'm gonna give the seafoam a try too..

that being said, i guess i could have explained the stalling a little better, but i think you might be on to something with the float, because had i had the fore sight to explain my predicamint a little better rather than giving all of the back story i did, i would have said that it sounds like the motor is flooding as it stalls, so the explaination that you're giving would make sense.

[NavanFisher]

Sounds like the carb might be dirty, take it apart, give it a good cleaning and that should do it...friend just bought a boat and same happened to his boat, cleaned the carb and voila...

good luck,

Tom

[clint]

I have a happy ending for everyone.....
Got working in the motor friday afternoon... Turns out for the time being the easiest fix worked, I got looking at all the connections first and came across a wire that had the sleeving crumbling away on it, traced it back to the mercury switch... With that being a mostly useless part I went a head and took it off..... Had it out saturday and it was back to running like new again well almost new anyways.....
Now on to trying to figure out the rats nest wiring on the trailer

[Raminator]

older mercs,alway's the wiring needs to be checked from the c box to the motor,then all the motor wiring,they are infamous for crumbling insulation.