48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses bad

[Beck]

Newbe here, Great Site, read many topics relating to my problem and Mr. Reeves has helped alot. He recommended I post here for additional input. Had 48 spl about 6 years only maint. plugs and lower unit lube change yearly. Rencently went out idles fine to about 2k rpm then engine misses so bad it feels like it will jump off transom. Joe informed my that my engine doesn't have the "slow" feature.<br />Not running hot, did test heat sensor it's seem ok. Thermostat clean and chamber not corroded. Joe informed me how to check the horn and it works when its grounded, doesn't come on when I turn on the key (will have to check that out further, may just run a test switch as the control box seems like it would be a pain to dissemble). The reason for all the over heat checking a local marine dealer said it was the "slow" feature. Had a 25 that did something similar and it was a bad/loose fuel line, I'm wondering perhaps the same here. Joe a clarification, you said to pump the fuel bulb with the fuel pump disconnected this would show a torn diaphram. And check by pumping bulb when engine starts to run badly will the fuel bypass the diaphram if they are not torn? I looked at them diaphram and they look ok just perhaps hardened?? If they are not torn is there a way to test? Any and all suggestions would be greatly appreciated. And sorry for the long post but just trying to give you the complete up to date.

 

[G DANE]

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

I would check to see if your stator moves freely when you advance throttle. If it is stuck you will experience axactly the problems you have. Remove hood from motor, identity throttle and ignition advance linckages and make someone throttle up with motor off. Does ignition advance all the way along with the throttles first movement ? It should.

 

[Beck]

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

G. Dane,<br />Thanks for the reply, and I did check that this morning all seems to move ok. I've been reading just about everything on this forum pertaining to 48 spl problems. I need to check the fuel supply to carbs. Joe R. recommended I pump the bulb when its starts to run bad (missing and engine rocking back and forth). Does this pumping bypass the fuel pump? I thought I would have gotten more input by now. I guess I should have listed the problem instead of the mod. & ser. numbers in the subject line. Oh well type and learn. Thanks again.

 

[rickdb1boat]

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

If you pump the bulb while it's running bad and it picks up and starts to run good, I would replace the fuel pump. It simply means that the pump is not doing it's job and you are manually forcing fuel to the pump and then to the carbs. when you pump the bulb. Does the bulb firm up when you pump it up? Does it stay firm when running? Have you tried a new bulb? No air leaks around the fuel fittings or hoses? I assume you have done a tune-up lately and replaced the plugs with the proper ones??

 

[rodbolt]

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

hello<br /> I have seen a few of those engines that the packs had some RPM related issues. the cdu2sl packs were under the flywheel and had slow. the cd2ul did not. a quick way to tell is look for the presence of a tan wire going into the pack.<br /> the other way to check is to hook up a peak reading analog multimeter and watch for flucuating volage at the coil primay towers. that should eliminate or confirm ignition. remember its intake,compression,ign at the proper time and exhaust, not magic to ID that pack CD is capacitor discharge, 2 is # of cylinders. U is underflywheel s has slow and l has a rev limiter. so if yours is mounted on the block it wont have a u, if it has no slow function it wont have an s if it has no rpm limiter it wont have L.<br /> <br /> good luck and keep posting

 

[Beck]

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

Thanks RB and Rodbolt for input.<br /><br />Went out few days ago w/o thermostat in to make sure it wasn't sticking and over heating, but Joe informed me I don't have slow. But while out it missed from the start actually about 30 sec into the run and did for an hour that we fished. (caught 6 specks while we were out there) any way back to the point. I noticed it missed bad even with the throttle lever lifted and running aprox. 2k-2300 rpm. but not in gear, just starting to idle to another spot to fish. When I got home took the fuel pump off the motor just to check it, didn't completely dissemble it but no trash and diaphrams seem slightly stiff not really rubbery? But put it back together and just a little while ago today still fooling with motor ran it and it ran perfect. Mind you, never did have any problem starting even cold 1-2 pushes on choke and this baby fired up. Its just 2000 some times 2300 rpm and she rocks back and forth like she will jump off transom. But today in my driveway with muffs on ran perfect. I did occasionly run her to 2500 rpm in nutual also put her in gear and ran her up a little more ran perfect. I know I need to put her in the water to really check it, but perhaps the prop back pressure making a difference?? Or hopefully fooling with the fuel pump helped something (wishful thinking). Anyway I will keep you informed. And thanks for the input.<br /> <br />Ps: Just found this site/forum and the wife can't keep me off the comp. Later guys. <br /><br />Pss: Sorry for the long post, but just trying to give all details.

 

[Beck]

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

Rodbolt,<br />Question for you the cdu2sl/cd2ul you speak of, where are these #'s?<br />My power pack is on the side of the block.<br />I do not have slow, and I'm not sure of limiter??<br />I will check when you tell me where to look for the numbers.<br />Thanks

 

[rickdb1boat]

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

 

[Beck]

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

Hi To All,<br /><br />Today checked fuel pump diaphram, pumped bulb with fuel pump off engine no fuel from vacuum port. Put finger on hole on block turned engine over felt pressure not sure of vacuum as it was difficult pulling roap and finger on hole.<br /><br />Checked high speed jets both clean and fuel from carb very fresh and not a bit of trash. Did this while carbs on engine did not remove the bowls. #'d on jets <or4 then 9D best I can tell. Flushed fuel through carbs when drain plug and jet was out, fuel seemed equally draining from both carbs.<br /><br />Power pak #583740 22LN-OA ,no OMC like in pic,<br />Spark plugs that are in engine now:QL78YC champion<br /><br />Pulled plugs they look clean, looked inside at piston top slightly carboned and oily looked good althouhg not sure what I'm looking for.<br /><br />Installed a guage in the fuel line between pump and carb pumped bulb naturally got pressure aprox. 9-19 lbs. then pressure dropped to about 5#'s and stayed. Have clamps on most fittings now took tyraps off.<br /><br />I'm heading out now for a test run in the bayou, it ran perfect in my driveway with the muffs on.<br /><br />Thanks, <br /><br />Ps: Question, when checking spark am I putting a screwdriver in the wire end and grounding to the plug or to engine block/ground?? Or do I need one of those spark plug checker things??<br /><br />Thanks again!

 

[Huey243]

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

Beck,<br />I have the same engine except it is a 1994 yr model and checked the power pack and the numbers on mine are like yours 583740 26IQ-OA<br /><br />I did a post on my engine problem and am eager to find out if you have corrected your problem.

 

[Beck]

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

Update<br /><br />When for a test run and as I took off from the dock it ran perfect for about 5 minutes. Though I had it fixed but then it started the same thing. Missing bouncing running awful. Lower throttle and it ran perfect to about 2000 rpm. Turned around to go back to the dock at fast idle 2-3 minutes tried it again and it ran at wot for about 10 minutes. Made several passes up and down the bayou then it started running bad again. Doesn't seem like the power pack is cooling down then working again?? Other than idling back to the dock for a few minutes, not sure if thats considered cooling down, any way the last time it acted up it never did start runing again at wot, just idling to 2000 rpm bact to the dock.<br /><br />Not sure what to do next, I guess it's be seen by a ob tech.<br /><br />Thanks for your assistance.

 

[G DANE]

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

Beck<br /><br />Are you sure its not the clutch dog in the lower unit thats failing, or your shift cable going bad. If thats the problem, everything will sound normal on muffs, but when its under load, motor will jump in and out of gear when it reaches i. exa. 2000 rpm. It will try to jump off the transom. Can you actually hear the motot miss beats, or does it rev up and down and jump ?

 

[Beck]

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

Re: 48 spl, m/n J48eslcer, s/n g02490337, idles fine up to 2k rpm , wot misses b

G DANE,<br /><br />Yes i'm sure it's not the shift dog, its shifts fine. When it acts up it's like missing mad, trying to run but just can't. Then sometimes for a short time it runs perfectly. <br /><br />I was thinking fuel but now i'm thinking perhaps electrical with the runing good then acting up.<br /><br />Today after work I will try a timing light to see if I can determine which cylinder is not fireing.<br /><br />Thanks for the response,