new battery and starter hard to turn over 175hp mercury sport jet

[molsenice]

helping a friend here - his jet boat will not start, he thought it was the starter which we replaced, also got a new battery. turning the key the engine turns 3/4 of a revolution and then it turns real slow for 1/4 turn before turning quickly for 3/4, repeat till you get the idea something isn't right.

Disconnect the battery and turn the engine by hand - same results, east, then hard, easy.

does not start as it comes almost to a dead stop when it gets hard to turn.

what should I look for?, do not want to end up chasing my tail here

thank you in advance

 

[canoemang]

Re: new battery and starter hard to turn over 175hp mercury sport jet

Is there any debris up in the impeller of the jet?

Maybe jet is shimmed to tight and rubbing on the liner.. if it has one or similar to a ob jet..

 

[boobie]

Re: new battery and starter hard to turn over 175hp mercury sport jet

I'd look closely for something caught in the jet pump as they act like a big vacuum cleaner.

 

[molsenice]

Re: new battery and starter hard to turn over 175hp mercury sport jet

ok well this is weird - nothing in the impeller, no obstructions.

so on a hunch I pulled the spark plugs to see if that made any difference as to the engine turning over.

well..... it did

the engine spun freely, which means it was hydro locking. either a blown head or cracked block.

unless I miss something major

a new rebuilt power head is 3200- ouch

soooo....

the guy gave me the boAt

now what????

 

[Timestep]

Re: new battery and starter hard to turn over 175hp mercury sport jet

I would simultaneously check the battery voltage, and the voltage on the starter. If the battery is being dragged down take it to an auto shop to be load tested.

This might reveal all ?

Dave