At a loss with mercruiser 470.

[rayfiftyone]

I Have A 1984 470 Mercruiser I/o. For Several Years I Have Been Having A Problem With Acceleration. Sometimes It Will Get Up And Run But Lately Its Getting Worst.it Will Not Run Wot. The Engine Sputters And Dies But Starts Back Up Just To Do The Same Thing. I Have Rebuilt The Carb Twice With A New Accelerator Pump. I Have Changed All Ignition Parts. I Have Drained All The Gas And Added Fresh Gas With A Treatment.i Have Replaced All Fuel Filters And Lines. I Replaced The Check Valve At The Tank.i Removed And Checked The Fuel Pump For Diaphram Leaks And To See If It Would Pump Manually--it Does.most Of The Times The Boat Will Idle In Gear At The Lowest Rpm But Refuses To Accelerate Without Stalling. The Timing Has Been Double Checked, The Points Have Been Replaced And Set Correctly. Coil, Plugs, Rotor , Cap, Wires,all Replaced. I Pulled The Distributor Out And Manually Checked The Whole Thing , Including The Centrifical Advance Plates For Sticking. All Is Good. The Carburator Floats Are Free And Set Right At Spec.what Is Wrong With This Engine? It Always Ran So Good..

 

[bruceb58]

Re: help with mercruiser 470!

Re: help with mercruiser 470!

When you tested the centrifugal advance, did you do it with a timing light to determine maximum advance?

 

[rayfiftyone]

Re: help with mercruiser 470!

Re: help with mercruiser 470!

No, I didn't.

 

[bruceb58]

Re: help with mercruiser 470!

Re: help with mercruiser 470!

Well, that's the only way you can accurately do it. You need to get and advance timing light or tape to put on the balancer to determine if its within spec.

 

[rayfiftyone]

Re: help with mercruiser 470!

Re: help with mercruiser 470!

Ok, I'll try that and see what happens. Thanks.

 

[Rocky_Road]

Re: help with mercruiser 470!

Re: help with mercruiser 470!

That is quite a list of repairs!

But you didn't mention doing a compression check....

P.S. Welcome aboard!

 

[rayfiftyone]

Re: help with mercruiser 470!

Re: help with mercruiser 470!

Yeah so I was really hoping that the advance was off, but it is just fine, also I did a compression check today as well and it is just fine as well...any other suggestions as to what may be wrong with my boat please?

 

[searay3]

Re: At a loss with mercruiser 470.

Sometimes new doesn't mean good. Parts do come bad out of the box. I would start with a trip thru the electrical/ignition components again. Maybe a shady coil or condenser...all cables and contacts clean and shiny? points installed correctly? Gotta be something maybe not grounded well, corroded connection. Take off the tach and condenser for a test run. Batteries/charging system up to snuff?

 

[cr2k]

Re: At a loss with mercruiser 470.

Time to replace everything between the flame arrester and the coupler, with non 470.