1957 35 hp misfiring like crazy

[Mr. Bwok]

Ok so I have had thE assistance of many to resolve my other issues now I have a new one. I have my 1957 rde-19 35 hp running, but I have a misfire. It has brand new coils , but older points and condensers. Before I grab some new points, I wanted to see if this could be a carb problem as well. Air leaking possibly? The is enough spark to jump a 1/2" gap, but I think something is amiss as throttle up. It starts to misfire, then pick up, then almost die, pick up misfire like mad then run rough until back on idle. E problem is I cannot tell with these big twins whether it is missing at idle as they run so well on one pot. Just to recap my work, compression 130/130, new coils, rebuilt carb, converted to single line, lower unit rebuilt, good spark, lots of fuel. Thanks in advance for the help. I will post my work as work to resolve. I am also trying to post a picture for everyone.

 

[Will Bark]

Re: 1957 35 hp misfiring like crazy

Are the spark wires on the correct plug? Have yu checked for a sheared flywheel key? Others will chime in with more suggestions. Good luck.

 

[Mr. Bwok]

Re: 1957 35 hp misfiring like crazy

Are the spark wires on the correct plug? Have yu checked for a sheared flywheel key? Others will chime in with more suggestions. Good luck.

I have not checked for the flywheel key, but I will pull it off and check now. I will post my findings. I guess I may as well do points and condensers at the same time. Stay tuned.

 

[nwcove]

Re: 1957 35 hp misfiring like crazy

have you tried backing off the low speed needle? i notice in your other thread on the same subject, that the welch plug fell out. are you sure the new one is sealing properly? if the carb sucks air from anywhere other than down its throat, the engine will be next to impossible to tune.

 

[HighTrim]

Re: 1957 35 hp misfiring like crazy

Does engaging the choke at all stop the coughing? Adjust the needle as nwcove mentioned?

How did you do your single line conversion? Did you modify the intake manifold?

 

[boobie]

Re: 1957 35 hp misfiring like crazy

There is a difference between cranking spark and running spark. Try some new points and condensers and gap the points properly.

 

[Mr. Bwok]

Re: 1957 35 hp misfiring like crazy

Ok so here is the new scoop on this. I pulled the flywheel and the key was perfect, no issues there. Looked to see if anything was amiss and found nothing, so zipped to the marina and grabbed points and condensers. Removed the coils as I wanted to make sure the plug wires were in ok and to leave me some room to work. Pulled first coil and noticed the ground wire had rubbed on something and was shorting, so I fixed that and installed the new parts, reassembled and voila 2 cylinders at idle. I also have an amzing top end now with both cylinders firing. The mid range is still not the way I want it, running a little rough, and almost like it is missing or starving for fuel or both. Once at full pin, it works perfect.

My fuel line conversion was done with a spare bypass cover from a parts block I own, drilled and tapped with a 9.9-35hp square pump that i had as a brand new spare for a couple of other outboards I own. I saved the original bypass cover and all the dual line stuff if I ever decide to restore two tanks. I have one tank, that has a good head, but the inside scared me to much to use it. I did borrow a perfect tank to test my motor before conversion. new gaskets, so not issues with that.

 

[nwcove]

Re: 1957 35 hp misfiring like crazy

NICE looking set up!! how much polishing did it take to make the boat look like that? your mid range issue could be as simple as dialing in the ls and hs jets . but again.....nice looking rig!!!!

 

[Mr. Bwok]

Re: 1957 35 hp misfiring like crazy

NICE looking set up!! how much polishing did it take to make the boat look like that? your mid range issue could be as simple as dialing in the ls and hs jets . but again.....nice looking rig!!!!

Thanks for the compliment. It took a lot of gel coat heavy cutting compound the get 55 years worth of neglect off of it. It also had some sanding done etc. polishing will be next summers project as well as the interior and some hardware. I will spend some time on the water working on the jets. I have the low speed one idling great, but it is hard to jump from the steering wheel to the back at WOT to adjust the high speed. If there is anyone near Marmora Ontario that wants to help, let me know. If not my neighbors are always curious as to what I am up to, so time to get them involved.

Would it be to rich or to, lean on the high speed?

 

[boobie]

Re: 1957 35 hp misfiring like crazy

Excellent looking boat. Don't see them like that any more.

 

[samo_ott]

Re: 1957 35 hp misfiring like crazy

Marmora? That's about 3 hours away! Bring it to Ottawa! Is that a Ranger or a Vagabond? I have a Lark on my Ranger. But I haven't polished it up yet. Eventually...

 

[kfa4303]

Re: 1957 35 hp misfiring like crazy

Awesome rig Mr. Bwok!!!! I love the old 35 hp Big Twins. She's gotta be a real head-turner at the dock. Glad you got that gem purring again. Happy boating!!!! Vroom-vroom....

 

[nwcove]

Re: 1957 35 hp misfiring like crazy

Thanks for the compliment. It took a lot of gel coat heavy cutting compound the get 55 years worth of neglect off of it. It also had some sanding done etc. polishing will be next summers project as well as the interior and some hardware. I will spend some time on the water working on the jets. I have the low speed one idling great, but it is hard to jump from the steering wheel to the back at WOT to adjust the high speed. If there is anyone near Marmora Ontario that wants to help, let me know. If not my neighbors are always curious as to what I am up to, so time to get them involved.

Would it be to rich or to, lean on the high speed?

no need for any extra hands to adjust the hs jet. make note of where its set now.at idle, open it up 1/4 turn, go for a spin and see if it gets better or worse. if it seems better, try another 1/4 turn out. if worse close it 1/4 turn from the original setting and see how it reacts. if the packing is tight and hs circuit is clean, you should find the "happy" spot.

 

[Mr. Bwok]

Re: 1957 35 hp misfiring like crazy

Well I found my ultimate problem. I was out trying to adjust the carb, opened it up, suddenly heard a rattle noise. Shut it down pulled the bottom plug and the electrode was Smashed down, like the piston hit it which is impossible, so I knew what the deal was. Got it towed home pulled the head and the piston is smashed to crap. Some foreign object went though it. I have a parts block , so I going to pull it apart and check condition. The cylinder wall seems to be in good shape upon first inspection, so I may be able to hone and swapo storm out of my spare block. If anyone has any advice, please fire away. This is my first time attempting this deep of a repair.

 

[kfa4303]

Re: 1957 35 hp misfiring like crazy

Hmmmm.......Before you do the tear down, what type of plugs are you using what fuel mix? Perhaps someone put new long electrode plugs in. You should be running Champion J6C plugs with 7mm copper core spark plug wires. You should also be running 24:1 mix. If those aren't it, then you'll probably have to take it all apart. I'm trying to think what sort of a "foreign object" could've done the damage:/

 

[Mr. Bwok]

Re: 1957 35 hp misfiring like crazy

Hmmmm.......Before you do the tear down, what type of plugs are you using what fuel mix? Perhaps someone put new long electrode plugs in. You should be running Champion J6C plugs with 7mm copper core spark plug wires. You should also be running 24:1 mix. If those aren't it, then you'll probably have to take it all apart. I'm trying to think what sort of a "foreign object" could've done the damage:/

J6c plugs nd 24:1 mix. I tore it down and what a mess. Piston destroyed, there was so much hard carbon inside the exhaust ports. It was inevitable. Both clinders scored, so new block iti is. I have a parts block and mid section that I tore down and it looks good. In the process of switching it all over. I am going to clean and redo all gaskets. At least I know what is inside this one. Rings are springy and Cylinders still have hone marks. Some one robbed this motors lower end and I bought the top for $10. For $10 I will tinker away and see what happens. Worse case scenario I have a boat that does not run. Oh wait that is what I have now.

 

[kfa4303]

Re: 1957 35 hp misfiring like crazy

That stinks :/ It's such a pretty motor, I still think it's worth the effort. You still won't find one as cool, or powerful for the same money. Keep us posted on your progress.