Merc. 40HP Salvage

[HeadHunt]

I have a 1992 40HP Merc. with bad compression. Still on my BassTracker with controls and trim. The compression is 110, 95, 125 and 115. I guess it will cost at least $1500 to rebuild the engine and I am not sure I want to put that much money into this boat. What could I sell this engine for? Or better yet, could I sell the boat, motor and trailer?

 

[Elmer Fudge]

Re: Merc. 40HP Salvage

Did you try decarbing? maybe you can get those comp numbers up a bit, they're not too far off.<br />Clean those carbs and see first,why unload the motor? are there other issues with it?

 

[HeadHunt]

Re: Merc. 40HP Salvage

Originally posted by Elmer Fudge:<br /> Did you try decarbing? maybe you can get those comp numbers up a bit, they're not too far off.<br />Clean those carbs and see first,why unload the motor? are there other issues with it?

Yes I decarbed. I may need to do it again. Its a long story what happened but in a nut shell, it sat for a long time(3 years) and I had to re-do the carbs, water pump, replace the control box and a few small things. Man it ran great afterwards, but for only a short while. It then became hard to start and started shutting down on me at WOT. Took it in and the mechanic discovered a leaking oil line so It probably did not get good lubrication. Do you think there is any hope?

 

[HeadHunt]

Re: Merc. 40HP Salvage

Originally posted by HeadHunt:<br /> I have a 1992 40HP Merc. with bad compression. Still on my BassTracker with controls and trim. The compression is 110, 95, 125 and 115. I guess it will cost at least $1500 to rebuild the engine and I am not sure I want to put that much money into this boat. What could I sell this engine for? Or better yet, could I sell the boat, motor and trailer?

Is it unusual for an engine to remain in service with these type of compression numbers? I would be more than happy to keep this Merc. if I knew it would be reliable.

 

[DHPMARINE]

Re: Merc. 40HP Salvage

HeadHunter,The numbers you post are low psi's for your motor,but there are variables,including compresion tester used,starter condition,battery voltage,and on and on.Usually I would expect 130 psi or higher.<br /><br />What caught my eye is these numbers will not shut down an engine at WOT,unless it seizes solid.Also the numbers are good enough that I would'nt expect hard starting.<br /><br />Maybe a second opinion as something else is obviously going on.( as well ?)<br /><br />DHP

 

[HeadHunt]

Re: Merc. 40HP Salvage

Originally posted by DHPMARINE:<br /> HeadHunter,The numbers you post are low psi's for your motor,but there are variables,including compresion tester used,starter condition,battery voltage,and on and on.Usually I would expect 130 psi or higher.<br /><br />What caught my eye is these numbers will not shut down an engine at WOT,unless it seizes solid.Also the numbers are good enough that I would'nt expect hard starting.<br /><br />Maybe a second opinion as something else is obviously going on.( as well ?)<br /><br />DHP

Thanks DHPMarine,<br /> I am going to pick up the motor tomorrow and take it to the lake to work on it, at least try some things. Aside from another decard and putting in new plugs what else should I do. I think I will mix a 50:1 ratio since I don't trust the oil injection. Any other thoughts?

 

[Clams Canino]

Re: Merc. 40HP Salvage

Yes... the numbers are a bit low, prolly needs a ring job, but not catastrophic numbers. I suspect there is more going on there - how did the symptoms 1st appear?<br /><br />-W

 

[HeadHunt]

Re: Merc. 40HP Salvage

Clams,<br /> About a month ago I decarbed with Deep Creep. The carbs were rebuilt about 6 months ago. Anyway, after the decarb I threw it in the lake and it ran great for about 30 minutes. The fastest it has ever run down the lake. On the way back to the lake house at WOT it just died. It didn't turn off, just went down to idle speed so I trolled back home. It felt like the throttle linkage and sure enough it was loose where it connect under the cowl so I tightened it up and the next day it started back up ok and ran good. Then on the way back home it shut down again at WOT and would not start back up so I pulled it out of the water. I checked the throttle linkage and it was OK so I put it back in the water and it took forever to get it cranked. After I got it started and gave it the gas it just shut down. I then took it to a mechanic in Brevard. He did a comp./ test and told me it wasn't really worth fixing. 110,95,125,115. He said they found a leaking hose from the oil injecter and the cylinders were probably messed up.It has been sitting at his place for a month. I plan on picking it up tomorrow and taking it back to the lake and messing around with it. thought I would do another decard and premix a 50:1 fuel. I really just want to sell the boat but want to get it running first. It is sitting on a nice looking Tracker and Trailer. I really appreciate your opinion.

 

[HeadHunt]

Re: Merc. 40HP Salvage

Clams,<br /> I am going to work on this engine tomorrow and I'll let you know what I find. I loaded up the cylinders with Deep-Creep today so it can work overnight.. I am picking up new plugs in the morning and I'll run it with the hose to try and blow the gunk out. The spark plugs looked real bad. They were coated with black stuff. When I start it up I may make a pre-mix with seafoam and 50:1 gas/oil. After I do that I will do a compression test and post my results. any other suggestions for tomorrow?<br /><br />Thanks,<br />HeadHunt

 

[HeadHunt]

Re: Merc. 40HP Salvage

I think I made some progress today with this merc. If you remember, my mechanic said it was not worth fixing because of bad compression (110, 95, 125, 115). I now think he may have been more interested in selling me a new motor. This came up several times. Here is what I did and discovered.<br /><br />1. First of all I loaded the cylinders with deep creep yesterday and let it sit overnight.<br /><br />2. I checked the compression this morning and got 98, 70, 100 and 96. Looked bad but I had not run it yet to blow out the gunk. I was also told to remove all the spark plugs when doing a compression test so I did. Is this the correct method?<br /><br />3. I mixed a gallon of 40:1 and poured in a can of seafoam into the mix. It took for ever to get it started on the hose. For about 30 minutes of trying the starter would only engage the flywheel for a couple of seconds and then kick out. It would not spin the engine for long at all.<br /><br />4. I finally got it started using starting fluid (ether) by spraying it into the carbs.<br /><br />5. I got it to run for 7 minutes at 2500RPM but I had to keep priming the bulb to keep it going. Sounds like a fuel problem.<br /><br />6. I shut it down and checked the compression again. 90, 90, 100 and 91.<br /><br />7. The number 2 cylinder really came up but my numbers were still very low compared to my mechanics. I changed the connector on my PSI guage and re-checked. I got 105, 100, 110 and 105.<br /><br />8. I really felt like I was getting somewhere now so I restarted the engine (still very difficult and I had to use more ether)and I ran it at 3500RPM for 8 minutes. I did not have to prime the bulb to keep it going this time but when I decreased the throttle down to 2000 RPM she shut down.<br /><br />9. I rechecked the compression with a good, tight fitting and came up with 107, 100, 110 and 105.<br /><br />I now believe this engine may just need a good tune up. I would love to here some opinions.<br /><br />Clams,<br /> Your opinion would be greatly appreciated. Would you consider working on this engine? I am only about 1 hour away. I lived in Anderson for about 7 years near the double bridges. I just do not think there is a mechanic around here I can trust to do the right thing.<br /><br />Please give me some ideas.

 

[Clams Canino]

Re: Merc. 40HP Salvage

HI! Answering in post with caps - easier. <br /><br />

Originally posted by HeadHunt:<br /> I think I made some progress today with this merc. If you remember, my mechanic said it was not worth fixing because of bad compression (110, 95, 125, 115). I now think he may have been more interested in selling me a new motor. This came up several times. Here is what I did and discovered.<br /><br />1. First of all I loaded the cylinders with deep creep yesterday and let it sit overnight.<br /><br />GOOD<br /><br />2. I checked the compression this morning and got 98, 70, 100 and 96. Looked bad but I had not run it yet to blow out the gunk. I was also told to remove all the spark plugs when doing a compression test so I did. Is this the correct method?<br /><br />YASSIR!<br /><br />3. I mixed a gallon of 40:1 and poured in a can of seafoam into the mix. It took for ever to get it started on the hose. For about 30 minutes of trying the starter would only engage the flywheel for a couple of seconds and then kick out. It would not spin the engine for long at all.<br /><br />THAT MEANS IT WAS KICKING, TRYING TO START AND THROWING THE BENDEX OUT EVERY KICK.<br /><br />4. I finally got it started using starting fluid (ether) by spraying it into the carbs.<br /><br />NEXT TIME SPRAY PRE_MIX - SAFER<br /><br />5. I got it to run for 7 minutes at 2500RPM but I had to keep priming the bulb to keep it going. Sounds like a fuel problem.<br /><br />YES IT DOES<br /><br />6. I shut it down and checked the compression again. 90, 90, 100 and 91.<br /><br />HMMMMMMM<br /><br />7. The number 2 cylinder really came up but my numbers were still very low compared to my mechanics. I changed the connector on my PSI guage and re-checked. I got 105, 100, 110 and 105.<br /><br />WHEW!!!!!<br /><br />8. I really felt like I was getting somewhere now so I restarted the engine (still very difficult and I had to use more ether)and I ran it at 3500RPM for 8 minutes. I did not have to prime the bulb to keep it going this time but when I decreased the throttle down to 2000 RPM she shut down.<br /><br />NEVER RUN IT OVER 2000 OUT OF GEAR.<br /><br />9. I rechecked the compression with a good, tight fitting and came up with 107, 100, 110 and 105.<br /><br />OK - NO FURTHER DAMAGE.<br /><br />I now believe this engine may just need a good tune up. I would love to here some opinions.<br /><br />I THINK IT NEEDS WORK ON THE FUEL SYSTEM FOR STARTERS <br /><br />Clams,<br /> Your opinion would be greatly appreciated. Would you consider working on this engine? I am only about 1 hour away. I lived in Anderson for about 7 years near the double bridges. I just do not think there is a mechanic around here I can trust to do the right thing.<br /><br />Please give me some ideas.

Well... since we've already been in email discussions about this motor for a week or so, it would prolly take less time to diagnose it in person than all this typing. I'll take it back to email, but once we're done with it - I'll post a follow up here so that everyone can learn from what it was.<br /><br />-W<br /><br />PS: Who stole my Avatar and why did we all get a reduction in ranking? I dissapear for TWO WEEKS and this place falls apart I tell ya' !!

 

[HeadHunt]

Re: Merc. 40HP Salvage

Thanks Clams. Lets make plans for me to drop this boat off at your place.<br /><br />HeadHunt

 

[Clams Canino]

Re: Merc. 40HP Salvage

Ok viewers, here's what we found out about this one when it came to the Clam-Shack (tm).<br /><br />My compresion tester put it a couple pounds on either side of 120 on all 4. <br /><br />It had "fuel system issues" in that the pump was leaking, and some of the hoses were loose and/or leaking.<br /><br />Further, the idle mixture screw on one of the carbs was closed *tight* and the idle stop screw was set way back at a place where it could not possibly run.<br /><br />I put a kit in the fuel pump, redid the gas lines, and reset the idle and mixtures. It will idle down to under 1000 easily, I can hear/feel some weepage at the upper reeds, not uncommon for a rig with 10 years and some miles on it.<br /><br />Then for good measure, I went against type and took a chance and replaced the water jacket cover gasket as it was leaking pretty bad at the #1 plug. Nothing broke, this was an educated chance based on the fact that it was "only" 10 years old and fresh water.<br /><br />*If* Headhunt *didn't* screw with the carb / idle settings, then the dealer he took it to left it worse off than when it came in, a common ploy to thwart easy fix's and sell new motors.<br /><br />This one... will live, though I advise against constant WOT on an "aging motor", the boat will go almost as fast at 4500, last longer, and burn a lot less gas.<br /><br />This motor was one of the last few years of the Super Thunderbolt powerheads, I showed HeadHunt my 1958 Super Thunderbolt.<br /><br />-W

 

[Scali]

Re: Merc. 40HP Salvage

Pretty inteesting thread, get a second opinion & or dont give up on checking it out even after shes been given a death sentence ..<br />If I was Headhunt, I'd be tempted to call the hack who he first brought it to & give him a piece of his mind

 

[HeadHunt]

Re: Merc. 40HP Salvage

First of all, let me say, Clams is amazing. I have been to at least 3 Mercury mechanics over the years and there is no comparison. His shop is very professional looking, he is honest and he obviously knows Mercs. inside and out. It was well worth the 85 mile drive to have him work on my engine. I strongly recommend you use his services if at all possible.<br /><br />About other mechanics. We really should start a thread where people can identify good mechanics within their driving distance, or maybe an entire topic on this message board. I would drive two hours, at least, to use a man I can trust to work on my engine properly.<br /><br />Now I am in a real dilemma with the mechanic that told me to trash this Merc. He is also a Honda mechanic/dealer and I purchased a BF115 from him about a year ago. Can I trust him to work on my Honda? Who knows... I know if I give him my 2 cents worth about the Merc. I can't take him my Honda anymore. I guess I will now be looking for a new Honda mechanic.<br /><br />Well, things seem to have a way of working out. In the interim, Clams_Canino, you are the man. Thank You!!

 

[Scali]

Re: Merc. 40HP Salvage

You could go to any authorized Honda dealership for service under warranty if you want, or @ least thats how it was with my OMC & Yamaha outboards I bought new.

 

[HeadHunt]

Re: Merc. 40HP Salvage

I guess that is my question. I have always gone to authorized dealers. I just wish there was some sort of grading system so you know who the good ones are.