Need second opinion

**ShadowFlier** · 05-13-2017, 03:44 PM

I recently bought a promax 225 that was supposedly rebuilt 20 hrs ago. I've put maybe half a hour to a hour on it and couldn't get it to run right. In the middle of a compression test I pulled the plug below out of cylinder #6. Then I pulled the head and saw that. What I don't understand is that the piston and cylinder wall look fine and don't have any nicks or marks. I pulled the other head and #5 didn't look as bad but also had nicks. So my question is is that is it possible the guy who rebuilt it put it back together like this and I should rip him a new one? Or was it caused by me in the one hr I ran it.

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**BUZZIN' DOZEN** · 05-13-2017, 04:15 PM

If your pistons and bores look fine, I'm thinking after the blow up, the rebuilder scrimped on parts and there was some recycling.
I've seen beat up heads reused, but he couldn't even pop for a new spark plug?

**tunnelmike** · 05-13-2017, 08:28 PM

What is the compression on that hole ? Mike

**ShadowFlier** · 05-13-2017, 08:35 PM

All were still 120 in each hole. I contacted him and he is sending me a used pair of heads for free. I'm hoping he didn't reuse any other parts that I can't see.

**W2F a V-King** · 05-13-2017, 11:02 PM

So one has to wonder did he just fix the symptom? Which was the melted piston/s and put it back together? Was the reason the 2 cylinders had the problem found and resolved?

Judging by the way it was rebuilt...I'd say no.

I wouldn't just replace the heads and go, but maybe get more info from him on what and why, if you can. And he better be sending you a new set of head gaskets and 6 spark plugs....new.

If you run it after installing the new used heads, I would want to run a leak down test. 20 hours should be enough for the rings to have gotten to set...."If" they are new.

Don't mean to sound negative, but I know first hand what it feels like to buy something used and it not be what was advertised.

**FORBESAUTO** · 05-13-2017, 11:47 PM

This is also another candidate to get the flywheel indexed to each cylinder and check wot timing on all cylinders. Cylinder 6 is one of the cylinders that gets the most timing when there is a bias problem between the switchboxes. If it wasn't fixed it will destroy a piston top in a hurry and dont even have to pushing it hard at all. Also need to make a part throttle run and shut off while running if your boat will allow it and look at plugs to make sure it has enough fuel in those cylinders. And then again at wot if boat will allow. Need to be cautious in case he only fixed the symptoms and not the cause so you don't damage it again. As W2F a V-King stated.

**90 5.0** · 05-14-2017, 12:22 AM

Why are you running those plugs in a Promax?

**whipper** · 05-14-2017, 12:32 AM

Ive been running surface gaps for ever no issues? ZHW But I have never had a plug look that bad before? That thing is shot!!

**Steve Pope** · 05-14-2017, 12:58 AM

make sure the heads are the same casting number as the ones on your engine. Pro max heads are unique

**tlwjkw** · 05-14-2017, 07:41 AM

i'd be real tempted ta take it completely apart and look at... looks like he didn't even attempt ta do it right... that head is jus plum nasty for a "fixed motor".. not even close ta passin' tha smell test!........jmo

**90 5.0** · 05-14-2017, 11:32 AM

Originally Posted by Steve Pope

make sure the heads are the same casting number as the ones on your engine. Pro max heads are unique

Exactly what differences are there? Only difference I can tell from an xri head is they are bare and have the water temp ports in them.

I I thought they were the same as a 260 head?

I have a couple sets of xri heads that are cut that I run with no issues??

**flabum1017** · 05-14-2017, 12:12 PM

How do the ports look? Are they chewed up from the rings passing though or did he put a sleeve in it?

**90 5.0** · 05-14-2017, 12:34 PM

If the piston and cylinder look fine I don't think there is anyway that could have happened to the head and nothing to the cylinder and piston.

Those would need need to be cut ALOT to clean up if at all.

Let me know what you want to do with them I want to get s tight set made that will require welding anyway so best to start with a messed up set than cutting and welding on a good set n

**ShadowFlier** · 05-14-2017, 01:23 PM

Originally Posted by flabum1017

How do the ports look? Are they chewed up from the rings passing though or did he put a sleeve in it?

Ports all look good. It really does just look like he put bad heads back on to save a few bucks but what I don't understand is why he reused a bad plug also. Tomorrow I'm going to take the reeds out and take a closer look at everything. Hopefully that was the only thing he reused.

**ShadowFlier** · 05-14-2017, 01:25 PM

Originally Posted by 90 5.0

If the piston and cylinder look fine I don't think there is anyway that could have happened to the head and nothing to the cylinder and piston.

Those would need need to be cut ALOT to clean up if at all.

Let me know what you want to do with them I want to get s tight set made that will require welding anyway so best to start with a messed up set than cutting and welding on a good set n

The guy I bought the motor from is supposed to send me a good pair. When ever I get them or buy some I'll let you know and just send them to you.