TOPIC: 1969 Merc 1000, 100hp....problem!!!

I have a 1968 Glasspar Avalon with a '69 Mercury 100hp...the boat and motor have been a dream the last 2+ years ive had it...but the last 4 or 5 weekends ive taken it out it has been acting up a little bit.

When i first bring it out and start it up, it starts fine...I pump the fuel bulb untill it starts the get hard, and then i bring the cold start up and choke it and it starts fine.

But then, after driving it for about 30 to 45 minutes, i will stop and swim for an hour or two...get back in and try to start it up, but it takes for ever...i have to hold the key and crank it for a while before it will finally turn over....Ive tried pumping the fuel pump, and ive tried not pumping it, ive also tried cold start on, cold start off....but nothing seems to work.

I dont know much about engines, but this last time i took off the spark plugs, cleaned them up with gas and that didnt seem to help at all...so any help will be much appreciated.

Id start with the easy things first...new plugs, decarb the motor with Seafoam, replace any fuel filters or slightly questionable fuel line and replace the fuel pump diaphragms...

After your 1-2 hour break, is the primer bulb still firm??

after your checking the items JerrfyLube mentioned and if it happens again pull the plugs when it wont start, to check to see if the plugs are wet, also take a spray bottle of fuel and squirt it in the carbs & again attempt to start

this will help isolate your problems faster

Is she pumping water? If not and she's overheating, might be hard to start until she can cool way down

When the boat is sitting while swiming do you notice any oil sheen
on the water around the motor? does the fuel ball stay hard when pumped for start up after 1-2 hrs shut down? try running the motor as normal but remove the wraparound and let me know.

Smoke

hey MadProps, when i pulled the plugs to clean them last time, i did notice there was a lot of residual oily greasy stuff on it, are they supposed to have anything on them at all...even if its been a year since ive taken them out to clean them? Also, if the plugs are wet...what does that signify? and is there any fluid that CAN be on them? sorry, like i said..."not that great at engines:)"

man i hope i can find the plugs for it...there pretty weird...they got a broad tip with a little ingrown nipple on them??? and what exactly is seafoam?...will most boating places have it? and last but not least...what is a fuel diaphragm and are they expensive?...thanks a lot for your help JerrfyLube.

peterstansky- im not exactly sure to tell if its pumping water...but i have taken it out and started it on land with a water jacket and noticed that after about a minute of being started, a little spout on the bottom of the engine case starts spouting out a little stream of water?...so, that being said, how do i definately tell its overheating?

Hey Smoke, I have noticed over time that theres a little oil sheen on the water, but its not so noticeable that i notice it every time i get back in the boat...i just figured its because it a dirty two-stroke:)...i really dont think its anything out of the ordinary though.

also, im not sure if the ball is hard after sitting for a while...but like i said before, i have tried pumping it and not pumping it...both didnt work. should it be hard? and what will removing the wraparound do?...what should i be looking for?

Seafoam and Seafoam Deep Creep spray are at most auto part stores and at Walmart . add regular Seafoam to your fuel tank (follow directions ) it helps keep carbs clean amongst other internal parts . to de-carbon your engine , get a can of Seafoam Deep Creep spray bring your boat to the lake , bring it out and warm it up . then get to shore pull the covers off the engine start it up and while keeping the engine running spray as much Seafoam in all three carbs until it stalls out , wait about twenty minutes, get it started take it back out in the lake and give it a few WOT runs . a couple times doing than should clean it out .

The little stream of water that you see coming out of the side of the motor (underneath the power head) is known as the 'telltale" (or sometimes "pee stream"). When the water impeller is functioning properly, you will see this stream appear a few seconds after the motor is started and running. It should be a goodly stream during idle, and a strong stiff stream underway. If this stream is weak or missing, it can be indicating that the impeller has worn out and is no longer pumping water sufficiently through the motor. As a result she'll run hot. If she runs hot enough, she can be hard(er) to start for a few hours.

Sometimes the "pee hole" from which the telltale spits gets clogged and would lead you to believe the water impeller is not working well. So check that to see if there is any build up around the pee hole that might fake you out.

These motors actually run fairly cool. With the cowl cover off, and the engine warmed up completely, you should be able to place your hand on the water jacket and it should be cool to the touch. On my '63 1000, the water jacket is on the right side of the motor if you are facing it from the front. Not sure about the 69's.

The water impeller (water pump) is located in the foot of the motor above the gear case, and should be replaced at least once every other season, and there are many whom feel it should be replace every season regardless of usage. If you use your boat regularly, have it replaced every season. Easy to do yourself, not expensive if you have a shop do it.

jchancegreen wrote:

man i hope i can find the plugs for it...there pretty weird...they got a broad tip with a little ingrown nipple on them??? and what exactly is seafoam?...will most boating places have it? and last but not least...what is a fuel diaphragm and are they expensive?...thanks a lot for your help JerrfyLube.

Plugs are available through Napa...they usually have to order them though. Same with the fuel pump diaphragms...follow your fuel lines from the carbs and you will find the fuel pumps...they are mounted on the side of the engine block...not overly familiar with your particular year motor but i believe you will find two fuel pumps. They are usually very easy to replace and require just basic hand tools to swap the diaphragms out which are nothing more than a little rubber flapper. While your at it, throw a new impeller in it too...cheap insurance.

Seafoam is often labeled as a "tune up in a can" but this stuff actually works. Everyone has their own methods of using it but ill share how i like to use mine. I put half the can into a spray bottle and spray it directly into the carbs while its running at idle after its been warmed up for a couple mins...it will cough, spit, smoke and run like crap when you are doing this. After youve put half the can through the motor, turn it off and let it sit for 10-15 mins and let it soak. Start it back up and take a hot lap around the lake to blow all the crap out. Id recomend doing this on a not so crowded lake, preferably on a somewhat breezy day as it will put out ALOT of smoke!! With the remainder half can, i mix it with about a gallon or two of premixed fuel and then again, take another couple hot laps around the lake at WOT till its gone. Really helps clear out any carbon or other nasty deposits in your motor and will keep your rings from sticking which is a big killer of two stroke engines. Seafoam is available at just about any auto parts store, walmart, etc for 6-9 bucks a can.

alright, so i just got through running the "engine tuner" in the moter...i replaced the spark plugs with brandnew ones...just in case, and by tomorrow i will start it again like the can says, and report back with the details.

i did try to notice if the pee hole was performing properly...here's what happened:
turned the engine on and after about a minute of it idling i was beginning to worry that i was burning the engine up, so i throttled it forward a little bit and water started coming out finally, but as soon as i put it back in neutral it stopped spitting out water. is this normal?

also, i talked to a mechanic about it and unplugging the fuel line is something he recommended when i let it stand for an hour or two...is this something people do with two strokes...my brother mentioned he did it on his dirt bike???

thanks again for your help guys!

as i put it back in neutral it stopped spitting out water. is this normal?

NO, it should put out a smaller but steady stream even at idle! It's time to replace the water pump impeller before you overheat it and ruin the motor, IMHO.

unplugging the fuel line is something he recommended when i let it stand for an hour or two...is this something people do with two strokes

Shouldn't be necesary, outboards won't feed fuel from gravity like a dirt bike with the tank above the motor. (I do unplug mine for a minute to run fuel out of the carbs after loading on the trailer, but plug it right back in.) This would be un-necessary, and be a way to introduce water or contaminants into the fuel system.

Just my two cents worth.....

Sounds like the motor is getting hot at idle, like before shutting down, and maybe vapor locking . Impeller should cure this.

thanks a lot guys...this sounds just like the problem!...ill report back when i get it replaced...does anybody know how much this impeller runs for...and can a guy like me replace one very easily? any pictures or diagrams would help.

jchancegreen wrote:

thanks a lot guys...this sounds just like the problem!...ill report back when i get it replaced...does anybody know how much this impeller runs for...and can a guy like me replace one very easily? any pictures or diagrams would help.

Usually 15 bucks or so for just the impeller...add another 15-20 bucks on top of that if you need the entire water pump kit(if you have bad gaskets)....again, available through Napa or pretty much any boating supply store.

Replacing the actual impeller is very simple...sometimes the lower units can be a pain in the butt to get off and on though. Make sure you use plenty of grease on the end of the drive shaft where it goes into the powerhead upon reassembly...they tend to weld themselves together if you dont.

thanks a lot...all report back when i have good news...have fun boating while im out of commision:)

I found changing out the impeller is fairly easy. My advice in addition to the above of greasing the end of the drive shaft;

If the water tube drops down, which runs from the top of the impeller housing to the bottom of the power head, make sure it slides into it's location in the power head when you are putting the lower back on. Mine slipped out without my knowing.

Above all, take pictures. Lots. Pictures of things you would never imagine you could forget or get confused about.

Good luck and let us know!!!

Dont some motors need to be in gear when removing the lower and reinstalling???

i really dont think im capable of doing this...im afraid im going to ruin my perfect motor. i called the local boat shop and they said it would cost about 180 dollars.....,.thats going to hurt my full time student pocket book:)

anyways, does anybody know a good website where i can find the specific part number for the impeller i need.

jchancegreen wrote:

i really dont think im capable of doing this...im afraid im going to ruin my perfect motor. i called the local boat shop and they said it would cost about 180 dollars.....,.thats going to hurt my full time student pocket book:)

anyways, does anybody know a good website where i can find the specific part number for the impeller i need.

Whats your serial number?

so i just spent the last 5 hours watching videos on you tube to see if this is something i could manage to do...and after attempting to take it off, i have chipped off alot of paint and still seem to be really stuck on the forward side of the gear case (the side closest to the boat)...it just wont seem to come down...like its glued or something...i was prying screwdrivers up there like crazy. any help with that would be great.

hey JerrfyLube, the serial number on my engine is: 2681453

This is the impeller you need:

www.iboats.com/mall/partfinder/?cart_id=043446024&gd_grid_id=927&gd_poid=110789&gd_row=123&session_id=207827976

Sierra Part number 18-3017

Make certain you got ALL the bolts and nuts off...theres a hidden one that holds the trim tab\anode in place...as well as two underneath, the one in the front and the two nuts on the sides.

If its still stuck, your drive shaft might be stuck in the power head, in which case, all i can do is wish you luck! Dont get overzealous with the pry bars...you can and will break cast parts VERY easily. Make some wooden wedges and put them around the edges in between the mid and lower unit and tap them in gently working your way around. Watch out because when it does let go, its a toe smasher!!

yeah i got all of the same bolts off...its probably the drive shaft:(....ill try the wedges and get back with yall probably tomorrow.

also, how did you find the part number for my engine...i think i probably should replace the water pump while im in there...there usually pretty cheap right?

The impeller is essentially your water pump...at least, the heart of it and what does the actual pumping of the water. There are other gaskets and seals in there that you could replace if necessary but more often than not, all you need is the impeller if your careful taking everything apart. The part number for the entire kit i THINK is 18-3517 but might want to double check that.

If you look at the iboats page, specifically at the impellers, they fall within certain serial number criteria which helps determine the exact part you need.

Good luck!

Alright, so i got the lower gear case off with help from my neighbor. After i took the bolts off to the water pump, i spent the next thirty mintues trying to take that bastard of an impeller off...my drive shaft was all rusty, and so was the inside of the impeller.

Is there a standard cleaning process as far as lubing, and cleaning and replacing stuff???

thanks again...standing by:)

The inside of the impeller is (should be) brass, but you can clean up the driveshaft with WD-40, PB Blaster, whatever and steel wool or scotch-brite pad. Then use water resistant grease liberally on the entire shaft EXCEPT the very end that goes up into the powerhead. (Grease the splines, just not the end of the shaft.) I also grease up the water pump housing the impeller rides in to make sure it doesn't run dry during the initial start up after replacement.

what exactly are the splines? and to me, the impeller didnt look bad...did it go bad because there was to much rust?

if there is old rust & debris in the pump housing area, sounds like the blades of the impeller are shot, when you ran the motor it would have wore down the blades till they no longer pump sufficient pressure in seconds

the splines being referred to are on the end of the driveshaft

so when he said grease the splines just not the end of the driveshaft...he meant dont put any grease on the very top of the drive shaft

Yes sir, that's exactly right. If you put any grease on the flat tip/end, it can prevent the driveshaft from engaging fully (sliding up) into the powerhead.

wont prevent it from engaging but will preload the bearingc in the motor and lower unit.

well, i got the impeller in today, i plan on putting it back together tomorrow. before i do, i just wanted to get some last minute advice.

1. I was told that vaseline would be a good lubricant for the impeller and water pump housing...is this true?

2. What is the proper way to drain the gear case oil? I bought some tubes of stuff labeled "gear case lube", they told me that is was the same as gear case oil, even though ive seen videos of people using gear case oil that looks like the same container you use in cars instead of tubes. Is this the right stuff?

3. Last but not least...is there a proper way to put the impeller and the gear case back on the motor? What gear should it be in?


Thanks guys

The motor is back together and i cant thank you guys enough for your help...couldnt have done it with out yall.

Glad ya got it figured out!

Make sure you do a complete function check on everything before you take it to the lake...check to make sure you have proper functioning of forward, neutral and reverse and check to make sure your pumping water then go blast it around!

yep, did all of that...i actually duplicated the problem i was having before.

i started and ran it at a higher rpm ranger for about 15-20 minutes to simulate boating on the water.

then i let it sit for about 2-3 hours and restarted it...started like a champ like it used to.

as soon as i knew i did everything right (forward, neutral and reverse), i called my buddy in california and asked him if he ever changed his impeller or lower gear case oil....sure enough, just like me, he had no clue you were supposed to change those that often. everything is A-OK now!, cant wait to take it out this saturday.

Way to go dude!!! That's the beauty of this site. Have a Great time!