Popular Mechanics 1962 PM38 Build [SPLASHED 2017]

[pekstrom]

Hmmm couldn't get the link to work. One odd ball thing happened to a friend of mine, he had a new fuel hose that had a pin hole on the tank side of the bulb. It didn't leak fuel but let air in the line causing him to loose prime. Long shot but might be another thing to look at. Your tank does have an open vent? Probably not that, just brain storming!

Yeah, the site keeps replacing the hostname part of the URL. You can replace all the '*' with '**********' and it should work.

Hmm, I'll have to take a close look at my hose. I haven't noticed anything but then I haven't been looking for it either. Thanks for the tip. I'll take a look. The tank does have an open vent in the lid so there's ventilation there. Thanks for the ideas!

Just noticed this site sure doesn't want to share hostnames! :lol: Replace the '*' with boats dot net and it should work.

 

[pekstrom]

I have ordered a new gasket set for the carb. I don't want to take it apart and not have replacements in case some break. It is probably a good idea to replace them either way when I take it apart, so I don't introduce new problems because of poor seal by a used gasket.

When I cleaned it last year, I only soaked it in the carb cleaner bath for maybe an hour. So in reading some other posts it seems it may need to soak overnight. So I'm hoping it is just the carb that's gummed up still. And maybe that the float needs some adjustment as well. We'll see. Unfortunately the gasket set won't get here until late next week, so no lake this weekend.

 

[pekstrom]

Alright, I finally had time today to take the carburetor off the outboard and give it a good cleaning. I soaked all the parts in the carb cleaner bath for several hours and also used a spray can carb cleaner and blew it through all the tiny channels. Put all new gaskets and diaphragm on it and assembled it again. I double-checked the bolts holding the adapter plate and reeds in place, then put the carb back in place with a fresh gasket and made sure I tightened the nuts holding it properly. I did notice when I took it off that those nuts weren't tightened very much, so I may have had an air leak.

Another thing I noticed was that the timing link that goes from the choke/fast-idle adjustment arm to the trigger arm under the flywheel had slipped out of the arm. So when the adjustment was changed the timing didn't follow. So I fixed that while the carb was off.

I pulled the boat out in the driveway and filled a tub of water for it to run in. And then I cranked it up. I am happy to report that it actually runs much better now. It idles pretty well and seems to do ok idling in gear as well.

Here it is idling in neutral and is hovering around 750-800 rpms:

Here it is in forward gear and hovers around 650-750 rpm:

It does still surge at times and then drops back down. At times it drops below 600 rpm and almost stalls. It usually recovers though. I'm not sure why it does that at this point. I'll have to analyze it a bit more. I have noticed that the bulb on the fuel line never gets that full feel to it. When I squeeze it, I can squeeze it about half way before I feel fuel flowing through it. So perhaps I need a new fuel line. I can't see anything wrong with it but I would think that bulb should fill up after a few squeezes.

Now I need to take her out on the lake and see how it does there. And if it still runs rough on the lower rpms.

 

[archbuilder]

Sounds like you are making progress. Your bulb should get really hard once if fills up, did you check your float level?

 

[pekstrom]

Sounds like you are making progress. Your bulb should get really hard once if fills up, did you check your float level?

That's how I remember it from our old Chrysler I used as a kid back home. After 2 or 3 squeezes it got hard and I couldn't squeeze it anymore. So I guess a new fuel line is a good place to start. My tank is an old metal tank I got with the motor. If a new line doesn't fix that issue I guess I may need a new tank.

I did check the float and had to adjust it slightly. I used a digital caliper set to 0.8mm like it said in the service manual.

 

[pekstrom]

I did indeed have the primer bulb oriented the wrong way. The fuel line came assembled with a longer section of hose from the bulb to the engine. And a shorter to the tank, so it just ended up near the tank. Yesterday I took it apart and changed it so the bulb is now hanging vertically in the right direction from the engine. And the longer section goes to the tank. The bulb does seem to get firm this way now. I'm going to head to the lake in a little bit to test things out properly.

Thanks for all the tips and advice!

 

[archbuilder]

cool hopefully that solves your problem!

 

[pekstrom]

Well if it isn't one thing it's another. So the engine started pretty easily on the 2nd or 3rd crank and didn't run as rough as it used to. It did great on idle, at least in comparison to before. The id;e rpm may still be a bit high so the gears went in a bit rough. But I was able to coast on idle in forward without problems. But, turns out something is wrong with the primer bulb. The flow arrow is pointing to the engine so it is turned right. But squeezing it, instead of getting firm, it collapses and takes quite a while to come back out. And that resulted in the engine dying when I sped up. So new bulb it is. The engine doing much, much better made me very happy though!

 

[Scott Danforth]

stay away from attwood primer bulbs. never found a good one myself.

 

[sphelps]

I’m sure you already checked but is the tank vented well ? If not vented I would think the bulb would stay collapsed .

 

[pekstrom]

stay away from attwood primer bulbs. never found a good one myself.

Well, darn, I already got one and installed it. Ah well. I'll give it a try. It feels better and doesn't seem to be collapsing like the old one did.

 

[pekstrom]

I’m sure you already checked but is the tank vented well ? If not vented I would think the bulb would stay collapsed .

Yes, I did check that when I discovered the issue. The vent is open on the tank and has never given me problems before. We'll see if the new bulb makes a difference.

 

[archbuilder]

sounds like you maybe on to the culprit!

 

[pekstrom]

Alright, been out on the lake for a couple of hours and the engine behaved pretty well the entire time. Even at WOT. Well, WOT for a little bit, then it acted like it got fuel starved and the rpm dropped a bit. It felt as if the prop slipped in the water so the speed dropped a couple mph. If I didn't push it all the way it did good. WOT rpm was 5300 rpm so pretty close to recommended 5500-6000 rpm range. The new bulb worked well but what happened at WOT puzzles me a bit. I have noticed it a couple of times before with the old bulb as well. Not sure why it would do that? I may see if I can get the idle rpm down a bit more. It is a bit rough to get in gear, especially reverse.

We also did a good deed this evening. We came up on a 24-foot pontoon boat drifting with no gas. They were getting close to land and were getting worried. They had called their boat club for towing help but by the time we got to them it had been almost 30 minutes since they called. They tossed us a line and we spent 20 minutes or so slowly pulling them out from land. After that the club boat showed up and towed them in to the marina. The sad thing is they told us we were the first to stop and help them. I'm glad we were able to help out. Although it probably looked funny with this little 13-footer towing something that big.

 

[archbuilder]

Good for you, been towed, and towed people....it happens!

Sounds like you are making progress, trust me I did the same drill with Miss Morgans Merc. I had an issue like that but it was the fuel pump. Do you have a fuel filter? just brain storming.....seems odd with everything that you have done. I was really hoping you were over the hump!

 

[pekstrom]

Good for you, been towed, and towed people....it happens!

Sounds like you are making progress, trust me I did the same drill with Miss Morgans Merc. I had an issue like that but it was the fuel pump. Do you have a fuel filter? just brain storming.....seems odd with everything that you have done. I was really hoping you were over the hump!

Oh yeah, I have been towed a few times as a kid in our inflatable so I have learned we need to work together out on the water. I was sad to hear that there are some who don't feel that way. Just thinking ahead for a time when I'll need a tow. During the time we were helping them there were several boats, larger than ours that just blew right past us and didn't even look. Anyway, stepping off my soapbox...

Yes, I am quite happy with the progress so far. It is running so much better so now I am hopeful again. I do have a fuel filter in the motor. I just replaced it a bit ago so it is pretty much new. One thing I have noticed is that the primer bulb doesn't get firm as I pump it. If I disconnect the line at the motor the bulb goes firm since the valve in the fitting closes. So that makes me wonder if I have a leak somewhere in the engine. I don't see fuel anywhere under the cowling. And I haven't noticed any in the water without the engine running. So perhaps if I have such a leak, it could also affect the fuel supply at high rpms? I have also read that Mercury has designed their own primer bulb to work better with their engines. So I am thinking of getting one of those to see if it makes a difference. Seems the fuel pump should be good since I have had it apart twice and replaced the diaphragm and gaskets each time. Otherwise I'd suspect that too.

 

[zool]

Sounds like you may have a small particle clogging a jet when under high pressure....My center console started doing that and would almost feel electrical cuz the cutoff was so sharp....just a thought.

 

[pekstrom]

Sounds like you may have a small particle clogging a jet when under high pressure....My center console started doing that and would almost feel electrical cuz the cutoff was so sharp....just a thought.

Oh really? Did yours die completely or just kinda slack off a bit? Mine just slacks off a bit and comes back a few times. I haven't kept it WOT though so I don't know if it would continue and get worse. I ease off the throttle a bit and it goes away. But it is a very abrupt change when it happens. It sort of reminds me of driving a car that looses traction and then regains it.

 

[zool]

It wouldnt cut all the way out, just to maybe 1/2 to 3/4 throttle, then back to full sometimes....I spent alot of time swapping coil packs and other electric stuff, but was the carb setup.

 

[pekstrom]

It wouldnt cut all the way out, just to maybe 1/2 to 3/4 throttle, then back to full sometimes....I spent alot of time swapping coil packs and other electric stuff, but was the carb setup.

Oh wow. I don't think mine cuts out that much but it is definitely noticeable. After cleaning the carb twice now, I sure hope I don't have lose particles left inside it! :facepalm: I am thinking mine may be set a little on the lean side. The manual says to set the low-speed needle to 1 1/4 turn out from lightly seated as the initial setting. I then had to adjust it inward so I am slightly less than 1 turn from lightly seated. I wonder if that could have this effect as well? I am going to see if I can tweak it to slightly less lean and also get the idle rpm down a bit more. I don't want to run it leaner than I have to, knowing what insufficient lube can do to an engine.