Overheating ,I broke down took to shop

[rocks]

150 mariner has been running hot at high rpm's for awhile so I took it in.They ran compression all within 130-128 not bad for a ragged out 1983.They also said it wasn't fireing on #1and6.One of the harnesses from the fly wheel had some melted wires on it.My questions is will a engine run hot if 2 of 6 cyl. are not firing.

 

[KCLOST]

Re: Overheating ,I broke down took to shop

No, <br /><br />I can't remember if your temp. sensor is located under the #1 or #2 cylinder.. But if it is under the #2, and it wasn't firing, it would read significantly cooler than normal... As the temp sender is measuring head metal temps just near the combustion chamber for the top cylinder (which ever side it is on)... <br /><br />Sounds like you just have a water pump problem?

 

[rocks]

Re: Overheating ,I broke down took to shop

Klost,I believe it is under the #1 cylinder.I have replaced water pump,pop-it,therms,poppit seat,clipped 2 rings off poppit spring,new plugs the only thing i haven't done is unbolt the engine in 50ft of water.Thank you for your help in the past.

 

[rocks]

Re: Overheating ,I broke down took to shop

Klost,I believe it is under the #1 cylinder.I have replaced water pump,pop-it,therms,poppit seat,clipped 2 rings off poppit spring,new plugs the only thing i haven't done is unbolt the engine in 50ft of water.Thank you for your help in the past.

 

[KCLOST]

Re: Overheating ,I broke down took to shop

OK, first off don't mess with the poppet spring. That will not affect the temps at WOT...<br /><br />Let's start with the basics.... Do you have a water pressure guage? If so, what are the pressures at idle, no wake, and WOT...<br />If you don't have a pressure guage, are you absolutely sure you are not trimming out too far to prevent adequate water flow into the lower unit? I assume you are getting a constant alarm, is that correct? If so, does it matter what trim angle you have the engine at at WOT as to whether or not you have that alarm?<br />If your mechanics are going to service the motor, you might as well have them take a shot at the water jackets to check for blockages..<br /><br />Let us know...

 

[rocks]

Re: Overheating ,I broke down took to shop

Just got boat back,the trigger assy. had a few melted wires.According to them the engine was not fireing properly in some cases double fireing.They tested at lake and say it's not overheating anymore.I'm going to give it a run tonight.I've been chaseing this problem for awhile,Hard to believe it could have been elestrical.<br />KLOST pressure at idle 5psi at 3000 rpm 15-20 psi I cannot get a WOT because it would over heat at that rpm

 

[KCLOST]

Re: Overheating ,I broke down took to shop

Timing problem!!!!!! That has been known to cause an overheat condition...

 

[rocks]

Re: Overheating ,I broke down took to shop

I hope they are right.

 

[rocks]

Re: Overheating ,I broke down took to shop

Didn't work.They disconected the alarm to make it appear to work.Don't you love it.Test rode Fri. eve alarm at 3000 rpm. Then started testing,reved at nuetral no, alarm ran wot alarm after 1 minute.Let idol for 10 min. then powered up, alarm at 2500 rpm.This thing has got me stumped.I have replaced eveything but horn itself could that be a problem.<br /><br />P.S I took the cover off motor and felt the block after alarm and it was too hot to touch.

 

[KCLOST]

Re: Overheating ,I broke down took to shop

Sorry to hear about the shaft you received....<br /><br />I know you have replaced "everything" up to this point, but are you sure about the poppet valve being in good shape an clear of debri.... I kind of have a ? about getting 15-20psi at 3000 rpms... That seems a little high... It's possible the poppet is not opening... "maybe"<br /><br />I've also been reading that the "spark advance module" could be a culprit on motors that have been torn through top to bottom with no result... <br /><br />Let us know...

 

[catiiid]

Re: Overheating ,I broke down took to shop

Rocks,<br />You should post on every boat related forum you can find the name of that boat shop you took your boat to. No excuse for that type of business. At least let the owner know. Maybe he is unaware of how his mechanics treat people. Maybe you should call him first. If he doesn't take care of you., let the world know.<br /><br />ED

 

[KCLOST]

Re: Overheating ,I broke down took to shop

no doubt!!!!!<br /><br />And did you happen to notice your WOT water pressures?

 

[rocks]

Re: Overheating ,I broke down took to shop

Thanks for the reply,Not only did they disconnect the horn they also took my trailered boat to the lake without permission.On the way to the lake they left my bimini top up and shreaded it.Mechanic say's it happened in the water.Yeah right,I think they would know as it would have been hitting them in the head.<br /><br />KCLOST I did get a pressure reading at WOT on friday it held at 18psi then after a few seconds came down to 15 psi,but alarm was on so I pulled back.<br />PS It runs great now that all 6 fireing.

 

[rocks]

Re: Overheating ,I broke down took to shop

Update,Just talked to another shop they say I have a 30lbs pump and my current psi's are good.At this point I am lost,I've got you good people, that run these motors all day thinking 18-20 at Wot is too high.And possiby another crook saying it's ok.Any thoughts?? Thanks

 

[KCLOST]

Re: Overheating ,I broke down took to shop

No, No, No,<br /><br /><br />15-20 psi is not too high at WOT, it is possibly too high at 2500-3000 like you originally posted, that is when the poppet valve should open... At WOT you should see 20-25psi... If you are getting 30psi, that is too high and leads me to believe that the poppet valve is not opening properly...<br />If the poppet is not opening at the proper rpm, your water flow will be restricted to circulate through the heads to cool them properly.... Hence, that is why they call the poppet the "pressure relief valve"... Pull that baby out and replace the entire assembly, it's a cheap deal...