Merc 350 Thunderbolt trying to troubleshoot

[zark00]

I have an old Merc 350 Thunderbolt - I'm not sure the exact year as there's no decal anymore - but I think it's a '67.

Supposedly this ran fine maybe 2 yrs ago.

Motor's in neutral - prop spins freely both ways - but when I pull it the prop will spin. I can hold the prop with my foot and it wont turn, and it's no harder to pull.
It's kind of difficult to pull, it 'feels' like it's trying to turn the engine - kind of pulls out in two big jerks (if that makes sense).

I'm trying to determine what may be wrong with it before just giving up and taking it to someone to look at it for me. It's expensive though even to just have someone tell me what's wrong, and if it's serious I doubt I can afford to get it fixed. So I'm trying to get some idea before I pay $120 or more just to find out I have to pay another $800 to get it running.

Any ideas of what I can try? Thanks in advance.

 

[Yepblaze]

Re: Merc 350 Thunderbolt trying to troubleshoot

By your description it sounds as if all is well.

(well at least with the issue of the prop sort of turning, and the thump, thump feel as you pull the rope)

If you plan on rope starting that motor I would suggest you use a two handed, mansized swing.

And that it be mounted to a boat or something solid so your effort is to start motor, and not just take it for a dance around the garage.

 

[zark00]

Re: Merc 350 Thunderbolt trying to troubleshoot

Cool - thanks that's really reasuring.

I replaced the plugs with what the parts store told me were the autolite equivalent of the champion plugs that came out.
The manual though says to ONLY use Champion plugs - could that be part of the problme maybe?

 

[Yepblaze]

Re: Merc 350 Thunderbolt trying to troubleshoot

Autolite 303 's should be fine.