300/440/550 Hard cranking - not enough power..too much compression?

[Polish jet pilot]

I have a modded 550 (all the goodies including head). The engine is fresh, the starter is not, but it spins like crazy when I hook it up directly. Once I install it in the engine , it cranks fine for 1-3 times, later on it feels like the battery is dying (a good battery). The negative cable gets hot.

Is this beacuse of my higer compression? What can I do to make it crank better except for buying some high torque starter?

Becuase of thsi I got stranded in the middle of the lake a few times and had to paddle for ..long :aargh4:
Thank you!

 

[OCD Solutions]

I'd check all cables and connections first then jump the solenoid. If that doesn't sort anything then replace the starter.

 

[Polish jet pilot]

You think the solenoid is giving up? Could be... I will test it... What about if it turns out that the starter is generally ok, but too weak for thsi application? I heard people were adopting old seadoo starters for a 550...??

 

[chad]

if your cable is getting hot , I would guess its a short somewhere.. I would start and make sure your connections are good and tight !

 

[OCD Solutions]

I wasn't trying to point fingers at anything specific, just identifying possible suspects to be looked at.

I'm not familiar enough with the 550 starters to know if they are weak for that application so I won't touch that one but I will say that a weak starter will turn itself just fine and have no torque once load is placed on it and stall out very easy.

Usually the brushes get seized in the holders so the spring can't advance the brush to the commutator surface as it wears and the gap keeps on growing larger and larger until finally it can't sustain load anymore. Tapping on the outside can loosen a stiff brush so it can make contact once again and function but at that point it's days are likely already numbered due to corrosion or excessive or uneven brush wear.

 

[Matt_E]

if your cable is getting hot , I would guess its a short somewhere..

Not necessarily. I was recently working on a WB2 with tight crank main bearings. It cranked very slowly and the starter cable got so hot it was smoking. :biggrin:
The cable gets hot if it has a) too much current going through it or b) it is corroded, or c) both.
Too much current can be caused by a bad starter or by a motor that is hard to turn over.

OP: Once it slows down on the cranking, try cranking without the plugs. Does it still give you trouble? Can you turn the engine over by hand just fine?
Measure the resistance of the cable getting hot. If it's more than 1 Ohm, replace it.
I wouldn't suspect your relay or anything before the starter itself. (Because you seem to get adequate current to the starter).
You might get the starter tested at an automotive shop to see how much current it draws unloaded.

 

[Polish jet pilot]

Thanks for the comments guys. The engine is nicely built, turns over just fine. I guess its time to open up that starter and see what is inside. I 'm already making a new negative cable ( I checked the old one - inside it looked ok).

Must be the starter...

 

[WFO Speedracer]

If its the older type of starter that is a typical starter failure for those, I would either get the 92 and up style starter or a seadoo 587-567-717 starter

 

[Polish jet pilot]

WFO - that is good info there. Tell me if yo uknow, will the post 92 Kawi starter fit right in or modding is necessary? I guess the mounting holes could be different??

 

[WFO Speedracer]

Direct bolt in on the post 92 starter