'86 170/470 slow crank/no start after warmed up...

[Jersey13]

Hey guys. I've done a bunch of searching/reading the archives on this. My problem is, had the Wellcraft 192 w/Mercruiser 170/470 out yesterday. Started up cold fine, fished for a while, ran around for a while, shut it down for about 5 minutes and she didn't want to crank over fast enough to start. Starter was hot from motor heat. Let it cool down for a little over an 1/2 hour, cranked up quicker and fired up no sweat. Back to the dock after running at a good clip for about 10-15 minutes, shut her down and tried restrating, very slow cranking and just about stopped, and no start. Got home 1 hour later, cranked quick and started right up. Are these marine starters badly affected by all the heat generated in the doghouse and have a short lifespan? I'm thinking my problem has got to be the starter as i've read a bunch of different posts on this and have already done most of what have mentioned - new battery, new thick + & - cables, cleaned ALL connections. It's almost like when your timing is off or when you try to crank a high compression motor, but only after she warms up. Cold starts cranking is quick. Also, oil clean, fresh and not heavy viscosity, Exhaust bellows replaced recently and no water leakage, Engine temp runs nice even at WOT for a while - 165deg, timing checked OK, stator still in place and doing it's job properly. I've basically got it narrowed down to the starter, in my opinion, but would like to hear from the more experienced. Am i thinking in the right direction? If it is the starter, what's the best one to get that would last the longest? I think i had this one rebuilt about 2 years ago. Just seems odd that it would crap out this quickly...but it was very hot to the touch after running the boat around for a bit and it is enclosed unlike an auto starter that get air easily...Thanks much in advance for any help.<br /><br />- Jersey

 

[elpaso]

Re: '86 170/470 slow crank/no start after warmed up...

After running for 30 mins.- and shut down- is <br />starter hot before you try to restart of after ? <br />Do you leave blower on when running ? Do you let <br />engine idle for a few mins. before shutdown? Are you sure of engine temp ? <br /> <br />This engine has an aluminum block, if water circulation is impaired in block, and overheated<br />it can - swell - and seize the pistons. After<br />cooling down block will - shrink - and starter<br />will work. Has the t-stat been removed ?

 

[Jersey13]

Re: '86 170/470 slow crank/no start after warmed up...

Starter is hot to the touch before trying to re-start.<br /><br />I don't usually leave the blower running after initial 5 minutes before start up but i did try it the second time to see if it would keep the doghouse cooler which in turn, i thought, would keep the starter motor cooler and allow it to crank easier. It didn't work.<br /><br />Yes, i do let it idle for a little bit or run it slow to cool down after a run before i shut it down.<br /><br />Engine temp was checked by gauge which was double checked by meter. Runs at a good temp.<br /><br />T-stat has not been removed and works properly.<br /><br />Thanks for the reply. Keep um commin'! haha. I've worked on cars/trucks all my life and i'm not the type to just start throwing money at parts to see if they resolve the problem but, i think i'm ready to drop the $150 on the starter. I know I'm going to kick myself if it doesn't solve it though!!! lol. Thanks again.

 

[denniz]

Re: '86 170/470 slow crank/no start after warmed up...

cable size is very important 2.0 or bigger

 

[Jersey13]

Re: '86 170/470 slow crank/no start after warmed up...

2Ga + & -

 

[Northern Eclipse]

Re: '86 170/470 slow crank/no start after warmed up...

Jersey You stated that you have replaced the battery, What are the marine cranking amps ?? these big 3.7L 4bangers need at least a 800 to a 1000 cranking amp Battery, Smaller amp battery such as 550 cranking tend to drag the starter, thus the life of the starter will be shorter, I discoverd this about 10 years ago with my fathers Wellcraft 192 Classic 3.7L after many failed Batteries and 1 cooked starter, Since I changed up the Battery size, there has never been a hard or failed to start cold or hot

 

[Jersey13]

Re: '86 170/470 slow crank/no start after warmed up...

NE - i bought a new 550CCA battery the night before i went out (all they had in stock) I did want to go bigger but they didn't have one. I kept my old one that was fully charged as a backup in the boat and even tried to double up on the amperage by using both batteries to crank it over when i was stuck on the water and she still wouldn't crank! Well, slow cranking then no cranking. And like i mentioned, this only occurs after she warm and has run for a while - wether it be trolling or running at a good clip. Cranks right over and fires up no problem when cold or cooled down. I would have thought the 550CCA battery to be at fault too but, if that were it, it would crank slow cold or warm. Thanks for the info and suggestion. Appreciate it.

 

[Bob_VT]

Re: '86 170/470 slow crank/no start after warmed up...

It's the starter. Pull the starter and have it rebuilt by an automotive shop and tell the shop it is for marine use.<br /><br />Due to the age and location of the starter they tend to rust internally (more than you would believe)and it drops the efficiency of the starter to less than 50%.<br /><br />Been there...done that (just this year!)<br /><br />Bob

 

[Jersey13]

Re: '86 170/470 slow crank/no start after warmed up...

Thanks Bob, and to everyone else. I'm going to have the starter rebuilt and i'll go from there. Appreciate all the info.<br /><br />- Jersey

 

[jmatteus]

Re: '86 170/470 slow crank/no start after warmed up...

Jersey, <br /><br />Yep, my 84 Mercruiser 470 did the same thing. I replaced the starter and that fixed the problem.<br /><br />MileHighboater

 

[MrBill]

Re: '86 170/470 slow crank/no start after warmed up...

Jersey:<br /><br />Before pulling the starter, make a few quick checks of the distributor cap and rotor, if you're still with the original ig system. Every time I've ever had the "starts cold, won't start hot" problem (and its gets worse over time) the end result was cracked or damaged rotor, distributor cap, or other issue related to ig system, including coil. I've experienced this problem with my 3.7L, other Mercruiser engines, as well as auto engines and others.<br /><br />The 470 (and other 3.7L 4's) can be bears to turn over, but those starters are damn well built and usually only fail as a result of worn brushes. If your ig system (coil, cap, rotor,etc.) has not been replace in the last 5 or more years, head in that direction...let us know the results.

 

[skelly]

Re: '86 170/470 slow crank/no start after warmed up...

Jersey#13 Its the starter!!! my 79 470 did the same thing. They try to give you warning by acting up. SPEND THAT MONEY!! GO FISHING!!

 

[Jersey13]

Re: '86 170/470 slow crank/no start after warmed up...

Thanks Skelly for the reply. I put the new starter in wednesday night but have not had the boat on the water yet to see what happens. It does start right up and after it runs on the hose for a bit, i shut her down and she fires right back up. We'll see if this solves it. Also, re-did ALL the wiring just so i can't blame it Thanks again guys.