My Penta is having issues

Boatlovr

Recruit
Joined
Aug 18, 2013
Messages
3
My Penta is having issues

Boat ran beautiful prior to July this year. Winterized professionally every year since I purchased it in 2010 and had a rebuilt engine put in. Re- built 305 bored 30 over engine in 2010 new everything, rods, bearings, timing chain, oil pump

I put it in the water this year, started it, checked gauges as it was running at first, took my eye off temp gauge and proceeded to have fun then a few min later it beeped just a few times, stalled and shut down. Towed it in and took to mechanic. He found that it was the water pump and put in a new one. Hooked it up to the Muffs and started it. It ran fine, temp was fine, no water in the oil so he called me said it was the water pump its fixed and come and get it your luck and have fun. I Picked it up (took it to the water 700 miles away from home) a week later and attempted to start it. It cranked slow but did not start. I thought the batteries were dead (year 2005 batteries) because it was cranking slow so I replaced the 2 batteries. Same thing happened. I took it to local marina they looked at it an pulled all the plugs said I had water in the plugs and sprayed WD in the cylinders (PICKLED COMBUSTION CHAMBERS). They said that the exhaust manifold gaskets were shot most likely for sure and the exhaust elbow hoses were bad. Take it back home and repair it there because it was 4th of july weekend and no one was working that weekend. I got it to turn over fire right up before I left. Did not run it more than just a few seconds at the most.

took it home to and mechanic DID NOT check the exhaust manifold gaskets but did check the compression. The compression checked in at.

PERFORMED COMPRESSION TEST AND FOUND. 1=168,2=46,3=119,4=26,5=159,6=159,7=170,8=170 PSI. HAS INTERNAL ENGINE DAMAGE ON AT LEAST 2,4 AND 3 CYLS. NEEDS HEADS REMOVED TO FURTHER ESTIMATE. IF BLOCK IS OK, EST 2500-3000.00 TO REPAIR OR REPLACE HEADS AND REPAIR BURNT EXHAUST SYSTEM.

at this point I took it home to think about it or do more research.

This brings me to you all....

This is a lot of money for me at this point and it looks as if it could be even more money depending on what they find. I'm wandering if maybe it could be the manifold gaskets that could be causing the compression to be off? Or does anyone have any hopeful ideas?

Thank you!
 

captmello

Captain
Joined
Jun 30, 2008
Messages
3,855
Re: My Penta is having issues

Wow, you could just about buy a long block, 350 of course, and install it for that money...If you can't do the work yourself, you're going to have to pay.

You won't know until it taken apart.

Welcome, btw.
 
Last edited:

Boatlovr

Recruit
Joined
Aug 18, 2013
Messages
3
Re: My Penta is having issues

Thank you for the reply. Would the 350 long block be to heavy for the boat it is a 2002 starcraft aura 2015 20ft
 

erie_guy

Petty Officer 1st Class
Joined
Jan 16, 2007
Messages
269
Re: My Penta is having issues

I have had boats with both the 305 and 350 engines. I believe they are the same block and will be within a few pounds of the same weight. Most of the accessories should also be interchangeable.

erie_guy
Port Clinton, OH
 

skydiveD30571

Lieutenant Junior Grade
Joined
Feb 13, 2012
Messages
1,042
Re: My Penta is having issues

This is a lot of money for me at this point and it looks as if it could be even more money depending on what they find. I'm wandering if maybe it could be the manifold gaskets that could be causing the compression to be off? Or does anyone have any hopeful ideas?

Thank you!

To answer your question, no the exhaust manifold gaskets do not affect compression numbers. They simply stop exhaust water from entering back into the cylinders.

Let it be a lesson to you, there are many many good mechanics and many many not-so-good ones. I would never trust a mechanic (especially marine) enough to say something is fixed and then drive 700 miles to use it without trying it out locally first. Running on muffs can be useful to diagnose engine starting or idling issues, but the boat really needs tested in the water to prove it is fixed. It sounds like it overheated enough to do quite a bit of damage and all your mechanic did was replace a water pump? He didn't even catch the burned rubber exhaust boots which commonly melt with an overheating engine.

When two adjacent cylinders have low compression, many times it is a bad head gasket between them. That MIGHT explain cylinders 2 and 4. It might not. They are correct that the heads need removed to investigate.
 

81 Checkmate

Lieutenant
Joined
Jul 20, 2010
Messages
1,360
Re: My Penta is having issues

Just me....And i like to work/fix my own boat.

I would do a compression test myself to verify the readings.
Next pressure test the cooling system. See where the leak is
Pull the Exhaust manifolds and risers.
Pull off the valve covers.

A 350 is the same weight as the 305...just bigger piston bore hole.
 

fixnfly

Seaman Apprentice
Joined
Mar 3, 2010
Messages
38
Re: My Penta is having issues

I agree with 81 checkmate, buy a compression tester at a local automotive store. They come with directions, and easy to use. If the mechanic is right, pull the heads and check the gaskets.

If your mechanically inclined, do a vauum guage test, maybe a intake leak, worn rings, sticking valves, leaking valves, burnt or warped valves, weak valve springs, or head gasket leak. A vacuum test will tell you all this, if you have your factory manuals. Boatinfo - boat brochures and manuals for boats and marine engines! free manuals for download.

Keep us posted.
 

Boatlovr

Recruit
Joined
Aug 18, 2013
Messages
3
Re: My Penta is having issues

Thank you for your help everyone! this is a great forum. Yes I learned my lesson or a few of them with this issue. I'll let you all know the outcome.
 
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