Carb or worse?

alldodge

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1-3-4-2 is correct
No reason for it not to run, unless valves are to tight maybe. Is compression good?
 

Krsowles

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Alldodge, I’ve done some web scouring and am thinking it may be valves. Seems the most logical answer to why it acts as timing is off. I checked my compression and numbers weren’t great. 135,125, 170 and 120. I’m hoping the valve situation affecting those numbers some. I’m a little slammed right now so not sure how much time I’ll have to put into next week or two but love reading people’s thoughts and opinions, keep them coming!
 

alldodge

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135,125, 170 and 120.

Those numbers are bad with a fresh valve job. They should be more even

Would love to see 145 to 155, the 170 is way high even for a head which has been flattened
 

Krsowles

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I agree, not good at all. If valves too tight, can’t that allow some pressure to escape and skew the numbers? I went over block every which way with flat bar(?) and feeler gauges and it wasn’t out much at all but I’m human…
I want to loosen valves and try again.
 

Scott06

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I agree, not good at all. If valves too tight, can’t that allow some pressure to escape and skew the numbers? I went over block every which way with flat bar(?) and feeler gauges and it wasn’t out much at all but I’m human…
I want to loosen valves and try again.
No harm in loosening the valves and trying it, worst case it will clack and make some noise
 

Krsowles

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So I loosened the valves today to just 0 valve lash after going back to TDC compression stroke. I tried turning it over and it really wanted to start. I tightened them 1/4 turn tried again and it still really wanted to start, about the same as just a 1/4 turn. Then I went to 3/4 turn (as manual says) and it wasn’t as close to trying to start. I went back to a 1/2 turn past 0 lash and left it. Still no start. I did try moving the distributor in about 1/8” increments, either way an inch or so. Still nothing. I also got to smelling fuel so wondering if it may have been flooding out somehow. I wasn’t pumping throttle but I did have it about 1/2 down. I think tomorrow I’ll recheck compression and see if numbers still suck or if they straightened out at all. I can’t think of a good reason this motor won’t start but I know why I’m not a marine mechanic for a career! It has spark and fuel for sure and some compression. Thanks for any advice, enjoy the weekend!
 

alldodge

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Something is missing but I'm leaning toward spark. Might not be consistent
 
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In the earlier posts you mention the gas was 3-4 years old, and you topped off the tank with fresh gas. In your tests, did you check to see if the fuel would burn? Disconnect the gas line at the carb inlet, and let it pump into a container to get some fuel. Pour it in a clear jar along side some fresh gas and see how it looks.
Use a tablespoon and pour some gas you drew out of the tank on something that can take flame and see if it even lights. (away from any other open gas containers)

If you had any water in the tank, it will be sitting at the bottom of the tank where the pick up is. When you add fresh gas to old ethanol gas that has separated and has water in the tank, your new good ethanol free gas will be sitting on top of the junk that was in the tank.
 

Alumarine

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Have you tried pouring a couple of ounces of good gas down the carb and see if it fires?
 
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Krsowles

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I have not tried fuel down the carb yet. Will bring some 50:1 with me next time down and try. I have not checked for water in tank. Before I started this process the motor would run, although horribly. You knew all cylinders weren’t firing, power non-existent and it became quite loud exhaust noise. Stupid, I know as I write this, but fuel quality should be checked. I’ll do that as well, into glass jar for examination. I know it’s pumping a good amount of fuel and spray into carb barrels looks good. I also want to recheck compression as my numbers last time didn’t really make sense. Thanks for the input!
 

Krsowles

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I’ve found a donor boat I may consider as a donor for a motor. I need to do more homework on the motor but I know it runs well and have seen a video of it running. My question is this; the motor in question is a 1988 3.0 Mercruiser and I have a 1998. I have read they may not exchange so simply but can’t seem to find exactly why or if it’s worth pursuing. Does anyone out there have a better grasp on this info or point me somewhere I can do better research? I’d love any assistance I can get, thanks!
 

alldodge

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Don't think I would be throwing in the towel just yet but do understand the frustration. Since the change in rocker adjustment is so sensitive you might need new lifter.

If you go the donor route look for the serial number plate riveted on the block. It could be a 2.5L. The 3.0 will have serial number range of 0B450801 THRU 0C856558

You might need to use your engine coupler
 

Krsowles

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Thanks Alldodge. I hate to give up on motor but I’m not sure I’ll really trust it 100% after this. In my limited experience, I feel like once the head has been done the owner continues to chase problems that arise from initial failure or problem. I believe the motor overheated from what I’ve found but can’t even say for sure what caused the initial failure. I’d like to install a new motor but will need some time to “collect” the funds! If I could swap in one that hasn’t been through an overheat, I might get through this season, enjoying the boat instead of cursing at it in driveway. I’ll check the motor tag, as you suggest. I know the sticker on valve cover says 3.0. The throttle linkage to motor looks different and I keep hearing about flywheel and coupler may need to be swapped from my motor, if possible. Just not sure and was hoping a forum expert could wave a wand and dispel magic knowledge upon me. We all I know I can use all the guidance I can get! Thanks
 

Bondo

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See if we can hear from @Bondo
I know the sticker on valve cover says 3.0. The throttle linkage to motor looks different and I keep hearing about flywheel and coupler may need to be swapped from my motor, if possible.

Ayuh,.... The '88 was the Alpha 1, the '98 a Gen,II,.....
The flywheels will not swap, as the crankshaft bolt pattern changed in '90,....
But,.... I'm pretty sure the '88 will work with it's own flywheel, coupler, 'n flywheel cover,.....
As for the different throttle linkage, that also shouldn't matter once the cable is hooked up,.....

I'll end by sayin', I haven't done this swap, but I believe it'll work with very little creative engineerin',....
Oh,... The 2.5l has only a pulley on the front of the crankshaft, where the 3.0l has a pulley, 'n harmonic balancer,....
 

Krsowles

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Thanks Bondo, for the expertise! I’m leaning this way as a quick, short term remedy. Would allow me to possibly drop my 98 3.0 off at the engine shop and get it reworked properly. At that point I’m assuming it’ll be “like” a new motor going in, giving me years of trouble free service. That’s the thought process any how. I’ll keep you all updated, when I get back at it, enjoy!
 

Krsowles

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So I have what I hope to be a conclusion to my nightmare. I was pretty much conceded to replacing my motor. I found one locally for a good price and went to look at it. Turns out the guy selling it worked for years in the local boat shop until it was bought out and the new owners would not allow any moonlighting. The shop Forman left that day and opened his own place that has been thriving for years. Another long term mechanic did the same shortly after. That was the person I met selling the motor. We were discussing what I wanted to do and he was hesitant to sell the motor without further investigation. He asked me if I could drop the boat off to him. I told him I didn’t want a bill for him poking around unless it was necessary but I’d drop it off. He called me the next day and said my motor was running, he just needed to replace the spark control module (Aldodge). I told him I was seeing spark but he said it wasn’t enough. How could I argue, it was running! He used a part he couldn’t sell me and asked if I wanted him to order one. I said go ahead, please! It arrived and he installed it and it seemed to run great except water leaking at thermostat housing. He had a gasket to fix that and threw out the thermostat. That seemed a little odd to me, any thoughts? Anyhow, boat ran great and I was going to pick it up when he called and said cylinders 3 and 4 stopped working suddenly but then came back. It was dropping one or both of them randomly. He wanted to do a cap, rotor and wires and it was going to be a couple more days. I said go ahead, not sure what to think. We’re from the same town, have many of the same friends and acquaintances but I trusted him. He put those in, tightened a loose nut on a frame for motor mount. All for less than $600. The boat shop here is $140 an hour and takes forever to get in. This guy was $70 and the Forman that also left is $85 but still hasn’t gotten my smaller fishing boat in and I’ve been waiting since the end of June. Not a big $ maker for him, I understand that. So my boat runs pretty well now. Ever so slight stumble guy said was dirty carb but said he’d run it a little and see if it clears up. He’s happy to service/rebuild it but not sure it’s worth the $ yet. Curious what you all think, was I ripped off? I feel good about it so far, he could have just sold me the motor, helped me load it and let me struggle making it fit but instead, fixed mine for half what he wanted for the other motor.
 

Scott06

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So I have what I hope to be a conclusion to my nightmare. I was pretty much conceded to replacing my motor. I found one locally for a good price and went to look at it. Turns out the guy selling it worked for years in the local boat shop until it was bought out and the new owners would not allow any moonlighting. The shop Forman left that day and opened his own place that has been thriving for years. Another long term mechanic did the same shortly after. That was the person I met selling the motor. We were discussing what I wanted to do and he was hesitant to sell the motor without further investigation. He asked me if I could drop the boat off to him. I told him I didn’t want a bill for him poking around unless it was necessary but I’d drop it off. He called me the next day and said my motor was running, he just needed to replace the spark control module (Aldodge). I told him I was seeing spark but he said it wasn’t enough. How could I argue, it was running! He used a part he couldn’t sell me and asked if I wanted him to order one. I said go ahead, please! It arrived and he installed it and it seemed to run great except water leaking at thermostat housing. He had a gasket to fix that and threw out the thermostat. That seemed a little odd to me, any thoughts? Anyhow, boat ran great and I was going to pick it up when he called and said cylinders 3 and 4 stopped working suddenly but then came back. It was dropping one or both of them randomly. He wanted to do a cap, rotor and wires and it was going to be a couple more days. I said go ahead, not sure what to think. We’re from the same town, have many of the same friends and acquaintances but I trusted him. He put those in, tightened a loose nut on a frame for motor mount. All for less than $600. The boat shop here is $140 an hour and takes forever to get in. This guy was $70 and the Forman that also left is $85 but still hasn’t gotten my smaller fishing boat in and I’ve been waiting since the end of June. Not a big $ maker for him, I understand that. So my boat runs pretty well now. Ever so slight stumble guy said was dirty carb but said he’d run it a little and see if it clears up. He’s happy to service/rebuild it but not sure it’s worth the $ yet. Curious what you all think, was I ripped off? I feel good about it so far, he could have just sold me the motor, helped me load it and let me struggle making it fit but instead, fixed mine for half what he wanted for the other motor.
Sounds like he did u a solid. Seems reasonable considering its running. Have him rebuild the carb next
 

alldodge

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IMO it should have a thermostat
He shot gunned the entire ignition except Dizzy and now it works

Parts changer
 
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